root/chrome/browser/ui/webui/about_ui.cc

DEFINITIONS

1. GetAboutMemoryRedirectResponse
2. GetResponseResult
3. OnURLFetchComplete
4. OnDownloadTimeout
5. Start
6. StartOnUIThread
7. OnOnlineEULAFetched
8. LoadOemEulaFileOnFileThread
9. LoadEulaFileOnFileThread
10. ResponseOnUIThread
11. AppendHeader
12. AppendBody
13. AppendFooter
14. ChromeURLs
15. WrapWithTag
16. WrapWithTD
17. WrapWithTR
18. AddStringRow
19. AddContentSecurityPolicy
20. AboutDiscardsRun
21. AboutDiscards
22. Start
23. StartOnUIThread
24. StartOnIOThread
25. FinishOnUIThread
26. FinishMemoryDataRequest
27. AboutStats
28. AboutLinuxProxyConfig
29. AboutSandboxRow
30. AboutSandbox
31. BindProcessMetrics
32. AppendProcess
33. OnDetailsAvailable
34. profile_
35. GetSource
36. StartDataRequest
37. FinishDataRequest
38. GetMimeType
39. ShouldAddContentSecurityPolicy
40. ShouldDenyXFrameOptions

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/ui/webui/about_ui.h"

#include <algorithm>
#include <string>
#include <utility>
#include <vector>

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/callback.h"
#include "base/command_line.h"
#include "base/file_util.h"
#include "base/i18n/number_formatting.h"
#include "base/json/json_writer.h"
#include "base/memory/singleton.h"
#include "base/metrics/statistics_recorder.h"
#include "base/metrics/stats_table.h"
#include "base/path_service.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_piece.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/threading/thread.h"
#include "base/values.h"
#include "chrome/browser/about_flags.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/defaults.h"
#include "chrome/browser/memory_details.h"
#include "chrome/browser/net/predictor.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/profiles/profile_manager.h"
#include "chrome/browser/ui/browser_dialogs.h"
#include "chrome/common/chrome_paths.h"
#include "chrome/common/net/url_fixer_upper.h"
#include "chrome/common/render_messages.h"
#include "chrome/common/url_constants.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/browser/url_data_source.h"
#include "content/public/browser/web_contents.h"
#include "content/public/common/content_client.h"
#include "content/public/common/process_type.h"
#include "google_apis/gaia/google_service_auth_error.h"
#include "grit/browser_resources.h"
#include "grit/chromium_strings.h"
#include "grit/generated_resources.h"
#include "grit/locale_settings.h"
#include "net/base/escape.h"
#include "net/base/load_flags.h"
#include "net/base/net_util.h"
#include "net/http/http_response_headers.h"
#include "net/url_request/url_fetcher.h"
#include "net/url_request/url_request_status.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/base/resource/resource_bundle.h"
#include "ui/base/webui/jstemplate_builder.h"
#include "ui/base/webui/web_ui_util.h"
#include "url/gurl.h"

#if defined(ENABLE_THEMES)
#include "chrome/browser/ui/webui/theme_source.h"
#endif

#if defined(OS_LINUX) || defined(OS_OPENBSD)
#include "content/public/browser/zygote_host_linux.h"
#include "content/public/common/sandbox_linux.h"
#endif

#if defined(OS_WIN)
#include "chrome/browser/enumerate_modules_model_win.h"
#endif

#if defined(OS_CHROMEOS)
#include "chrome/browser/browser_process_platform_part_chromeos.h"
#include "chrome/browser/chromeos/customization_document.h"
#include "chrome/browser/chromeos/memory/oom_priority_manager.h"
#include "chromeos/chromeos_switches.h"
#endif

using base::Time;
using base::TimeDelta;
using content::BrowserThread;
using content::WebContents;

namespace {

const char kCreditsJsPath[] = "credits.js";
const char kMemoryJsPath[] = "memory.js";
const char kMemoryCssPath[] = "about_memory.css";
const char kStatsJsPath[] = "stats.js";
const char kStringsJsPath[] = "strings.js";

#if defined(OS_CHROMEOS)
// chrome://terms falls back to offline page after kOnlineTermsTimeoutSec.
const int kOnlineTermsTimeoutSec = 7;
#endif  // defined(OS_CHROMEOS)

// When you type about:memory, it actually loads this intermediate URL that
// redirects you to the final page. This avoids the problem where typing
// "about:memory" on the new tab page or any other page where a process
// transition would occur to the about URL will cause some confusion.
//
// The problem is that during the processing of the memory page, there are two
// processes active, the original and the destination one. This can create the
// impression that we're using more resources than we actually are. This
// redirect solves the problem by eliminating the process transition during the
// time that about memory is being computed.
std::string GetAboutMemoryRedirectResponse(Profile* profile) {
  return base::StringPrintf("<meta http-equiv='refresh' content='0;%s'>",
                            chrome::kChromeUIMemoryRedirectURL);
}

// Handling about:memory is complicated enough to encapsulate its related
// methods into a single class. The user should create it (on the heap) and call
// its |StartFetch()| method.
class AboutMemoryHandler : public MemoryDetails {
 public:
  explicit AboutMemoryHandler(
      const content::URLDataSource::GotDataCallback& callback)
      : callback_(callback) {
  }

  virtual void OnDetailsAvailable() OVERRIDE;

 private:
  virtual ~AboutMemoryHandler() {}

  void BindProcessMetrics(base::DictionaryValue* data,
                          ProcessMemoryInformation* info);
  void AppendProcess(base::ListValue* child_data,
                     ProcessMemoryInformation* info);

  content::URLDataSource::GotDataCallback callback_;

  DISALLOW_COPY_AND_ASSIGN(AboutMemoryHandler);
};

#if defined(OS_CHROMEOS)

// Helper class that fetches the online Chrome OS terms. Empty string is
// returned once fetching failed or exceeded |kOnlineTermsTimeoutSec|.
class ChromeOSOnlineTermsHandler : public net::URLFetcherDelegate {
 public:
  typedef base::Callback<void (ChromeOSOnlineTermsHandler*)> FetchCallback;

  explicit ChromeOSOnlineTermsHandler(const FetchCallback& callback,
                                      const std::string& locale)
      : fetch_callback_(callback) {
    std::string eula_URL = base::StringPrintf(chrome::kOnlineEulaURLPath,
                                              locale.c_str());
    eula_fetcher_.reset(net::URLFetcher::Create(0 /* ID used for testing */,
                                                GURL(eula_URL),
                                                net::URLFetcher::GET,
                                                this));
    eula_fetcher_->SetRequestContext(
        g_browser_process->system_request_context());
    eula_fetcher_->AddExtraRequestHeader("Accept: text/html");
    eula_fetcher_->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
                                net::LOAD_DO_NOT_SAVE_COOKIES |
                                net::LOAD_DISABLE_CACHE);
    eula_fetcher_->Start();
    // Abort the download attempt if it takes longer than one minute.
    download_timer_.Start(FROM_HERE,
                          base::TimeDelta::FromSeconds(kOnlineTermsTimeoutSec),
                          this,
                          &ChromeOSOnlineTermsHandler::OnDownloadTimeout);
  }

  void GetResponseResult(std::string* response_string) {
    std::string mime_type;
    if (!eula_fetcher_ ||
        !eula_fetcher_->GetStatus().is_success() ||
        eula_fetcher_->GetResponseCode() != 200 ||
        !eula_fetcher_->GetResponseHeaders()->GetMimeType(&mime_type) ||
        mime_type != "text/html" ||
        !eula_fetcher_->GetResponseAsString(response_string)) {
      response_string->clear();
    }
  }

 private:
  // Prevents allocation on the stack. ChromeOSOnlineTermsHandler should be
  // created by 'operator new'. |this| takes care of destruction.
  virtual ~ChromeOSOnlineTermsHandler() {}

  // net::URLFetcherDelegate:
  virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE {
    if (source != eula_fetcher_.get()) {
      NOTREACHED() << "Callback from foreign URL fetcher";
      return;
    }
    fetch_callback_.Run(this);
    delete this;
  }

  void OnDownloadTimeout() {
    eula_fetcher_.reset();
    fetch_callback_.Run(this);
    delete this;
  }

  // Timer that enforces a timeout on the attempt to download the
  // ChromeOS Terms.
  base::OneShotTimer<ChromeOSOnlineTermsHandler> download_timer_;

  // |fetch_callback_| called when fetching succeeded or failed.
  FetchCallback fetch_callback_;

  // Helper to fetch online eula.
  scoped_ptr<net::URLFetcher> eula_fetcher_;

  DISALLOW_COPY_AND_ASSIGN(ChromeOSOnlineTermsHandler);
};

class ChromeOSTermsHandler
    : public base::RefCountedThreadSafe<ChromeOSTermsHandler> {
 public:
  static void Start(const std::string& path,
                    const content::URLDataSource::GotDataCallback& callback) {
    scoped_refptr<ChromeOSTermsHandler> handler(
        new ChromeOSTermsHandler(path, callback));
    handler->StartOnUIThread();
  }

 private:
  friend class base::RefCountedThreadSafe<ChromeOSTermsHandler>;

  ChromeOSTermsHandler(const std::string& path,
                       const content::URLDataSource::GotDataCallback& callback)
    : path_(path),
      callback_(callback),
      // Previously we were using "initial locale" http://crbug.com/145142
      locale_(g_browser_process->GetApplicationLocale()) {
  }

  virtual ~ChromeOSTermsHandler() {}

  void StartOnUIThread() {
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
    if (path_ == chrome::kOemEulaURLPath) {
      // Load local OEM EULA from the disk.
      BrowserThread::PostTask(
          BrowserThread::FILE, FROM_HERE,
          base::Bind(&ChromeOSTermsHandler::LoadOemEulaFileOnFileThread, this));
    } else {
      // Try to load online version of ChromeOS terms first.
      // ChromeOSOnlineTermsHandler object destroys itself.
      new ChromeOSOnlineTermsHandler(
          base::Bind(&ChromeOSTermsHandler::OnOnlineEULAFetched, this),
          locale_);
    }
  }

  void OnOnlineEULAFetched(ChromeOSOnlineTermsHandler* loader) {
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
    loader->GetResponseResult(&contents_);
    if (contents_.empty()) {
      // Load local ChromeOS terms from the file.
      BrowserThread::PostTask(
          BrowserThread::FILE, FROM_HERE,
          base::Bind(&ChromeOSTermsHandler::LoadEulaFileOnFileThread, this));
    } else {
      ResponseOnUIThread();
    }
  }

  void LoadOemEulaFileOnFileThread() {
    DCHECK_CURRENTLY_ON(BrowserThread::FILE);
    const chromeos::StartupCustomizationDocument* customization =
        chromeos::StartupCustomizationDocument::GetInstance();
    if (customization->IsReady()) {
      base::FilePath oem_eula_file_path;
      if (net::FileURLToFilePath(GURL(customization->GetEULAPage(locale_)),
                                 &oem_eula_file_path)) {
        if (!base::ReadFileToString(oem_eula_file_path, &contents_)) {
          contents_.clear();
        }
      }
    }
    BrowserThread::PostTask(
        BrowserThread::UI, FROM_HERE,
        base::Bind(&ChromeOSTermsHandler::ResponseOnUIThread, this));
  }

  void LoadEulaFileOnFileThread() {
    std::string file_path =
        base::StringPrintf(chrome::kEULAPathFormat, locale_.c_str());
    if (!base::ReadFileToString(base::FilePath(file_path), &contents_)) {
      // No EULA for given language - try en-US as default.
      file_path = base::StringPrintf(chrome::kEULAPathFormat, "en-US");
      if (!base::ReadFileToString(base::FilePath(file_path), &contents_)) {
        // File with EULA not found, ResponseOnUIThread will load EULA from
        // resources if contents_ is empty.
        contents_.clear();
      }
    }
    BrowserThread::PostTask(
        BrowserThread::UI, FROM_HERE,
        base::Bind(&ChromeOSTermsHandler::ResponseOnUIThread, this));
  }

  void ResponseOnUIThread() {
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
    // If we fail to load Chrome OS EULA from disk, load it from resources.
    // Do nothing if OEM EULA load failed.
    if (contents_.empty() && path_ != chrome::kOemEulaURLPath)
      contents_ = l10n_util::GetStringUTF8(IDS_TERMS_HTML);
    callback_.Run(base::RefCountedString::TakeString(&contents_));
  }

  // Path in the URL.
  const std::string path_;

  // Callback to run with the response.
  content::URLDataSource::GotDataCallback callback_;

  // Locale of the EULA.
  const std::string locale_;

  // EULA contents that was loaded from file.
  std::string contents_;

  DISALLOW_COPY_AND_ASSIGN(ChromeOSTermsHandler);
};

#endif

}  // namespace

// Individual about handlers ---------------------------------------------------

namespace about_ui {

void AppendHeader(std::string* output, int refresh,
                  const std::string& unescaped_title) {
  output->append("<!DOCTYPE HTML>\n<html>\n<head>\n");
  if (!unescaped_title.empty()) {
    output->append("<title>");
    output->append(net::EscapeForHTML(unescaped_title));
    output->append("</title>\n");
  }
  output->append("<meta charset='utf-8'>\n");
  if (refresh > 0) {
    output->append("<meta http-equiv='refresh' content='");
    output->append(base::IntToString(refresh));
    output->append("'/>\n");
  }
}

void AppendBody(std::string *output) {
  output->append("</head>\n<body>\n");
}

void AppendFooter(std::string *output) {
  output->append("</body>\n</html>\n");
}

}  // namespace about_ui

using about_ui::AppendHeader;
using about_ui::AppendBody;
using about_ui::AppendFooter;

namespace {

std::string ChromeURLs() {
  std::string html;
  AppendHeader(&html, 0, "Chrome URLs");
  AppendBody(&html);
  html += "<h2>List of Chrome URLs</h2>\n<ul>\n";
  std::vector<std::string> hosts(
      chrome::kChromeHostURLs,
      chrome::kChromeHostURLs + chrome::kNumberOfChromeHostURLs);
  std::sort(hosts.begin(), hosts.end());
  for (std::vector<std::string>::const_iterator i = hosts.begin();
       i != hosts.end(); ++i)
    html += "<li><a href='chrome://" + *i + "/'>chrome://" + *i + "</a></li>\n";
  html += "</ul>\n<h2>For Debug</h2>\n"
      "<p>The following pages are for debugging purposes only. Because they "
      "crash or hang the renderer, they're not linked directly; you can type "
      "them into the address bar if you need them.</p>\n<ul>";
  for (int i = 0; i < chrome::kNumberOfChromeDebugURLs; i++)
    html += "<li>" + std::string(chrome::kChromeDebugURLs[i]) + "</li>\n";
  html += "</ul>\n";
  AppendFooter(&html);
  return html;
}

#if defined(OS_CHROMEOS)

// Html output helper functions

// Helper function to wrap HTML with a tag.
std::string WrapWithTag(const std::string& tag, const std::string& text) {
  return "<" + tag + ">" + text + "</" + tag + ">";
}

// Helper function to wrap Html with <td> tag.
std::string WrapWithTD(const std::string& text) {
  return "<td>" + text + "</td>";
}

// Helper function to wrap Html with <tr> tag.
std::string WrapWithTR(const std::string& text) {
  return "<tr>" + text + "</tr>";
}

std::string AddStringRow(const std::string& name, const std::string& value) {
  std::string row;
  row.append(WrapWithTD(name));
  row.append(WrapWithTD(value));
  return WrapWithTR(row);
}

void AddContentSecurityPolicy(std::string* output) {
  output->append("<meta http-equiv='Content-Security-Policy' "
      "content='default-src 'none';'>");
}

// TODO(stevenjb): L10N AboutDiscards.

std::string AboutDiscardsRun() {
  std::string output;
  AppendHeader(&output, 0, "About discards");
  output.append(
      base::StringPrintf("<meta http-equiv='refresh' content='2;%s'>",
      chrome::kChromeUIDiscardsURL));
  AddContentSecurityPolicy(&output);
  output.append(WrapWithTag("p", "Discarding a tab..."));
  g_browser_process->platform_part()->
      oom_priority_manager()->LogMemoryAndDiscardTab();
  AppendFooter(&output);
  return output;
}

std::string AboutDiscards(const std::string& path) {
  std::string output;
  const char kRunCommand[] = "run";
  if (path == kRunCommand)
    return AboutDiscardsRun();
  AppendHeader(&output, 0, "About discards");
  AddContentSecurityPolicy(&output);
  AppendBody(&output);
  output.append("<h3>About discards</h3>");
  output.append(
      "<p>Tabs sorted from most interesting to least interesting. The least "
      "interesting tab may be discarded if we run out of physical memory.</p>");

  chromeos::OomPriorityManager* oom =
      g_browser_process->platform_part()->oom_priority_manager();
  std::vector<base::string16> titles = oom->GetTabTitles();
  if (!titles.empty()) {
    output.append("<ul>");
    std::vector<base::string16>::iterator it = titles.begin();
    for ( ; it != titles.end(); ++it) {
      std::string title = base::UTF16ToUTF8(*it);
      title = net::EscapeForHTML(title);
      output.append(WrapWithTag("li", title));
    }
    output.append("</ul>");
  } else {
    output.append("<p>None found.  Wait 10 seconds, then refresh.</p>");
  }
  output.append(base::StringPrintf("%d discards this session. ",
                             oom->discard_count()));
  output.append(base::StringPrintf("<a href='%s%s'>Discard tab now</a>",
                                   chrome::kChromeUIDiscardsURL,
                                   kRunCommand));

  base::SystemMemoryInfoKB meminfo;
  base::GetSystemMemoryInfo(&meminfo);
  output.append("<h3>System memory information in MB</h3>");
  output.append("<table>");
  // Start with summary statistics.
  output.append(AddStringRow(
      "Total", base::IntToString(meminfo.total / 1024)));
  output.append(AddStringRow(
      "Free", base::IntToString(meminfo.free / 1024)));
  int mem_allocated_kb = meminfo.active_anon + meminfo.inactive_anon;
#if defined(ARCH_CPU_ARM_FAMILY)
  // ARM counts allocated graphics memory separately from anonymous.
  if (meminfo.gem_size != -1)
    mem_allocated_kb += meminfo.gem_size / 1024;
#endif
  output.append(AddStringRow(
      "Allocated", base::IntToString(mem_allocated_kb / 1024)));
  // Add some space, then detailed numbers.
  output.append(AddStringRow("&nbsp;", "&nbsp;"));
  output.append(AddStringRow(
      "Buffered", base::IntToString(meminfo.buffers / 1024)));
  output.append(AddStringRow(
      "Cached", base::IntToString(meminfo.cached / 1024)));
  output.append(AddStringRow(
      "Active Anon", base::IntToString(meminfo.active_anon / 1024)));
  output.append(AddStringRow(
      "Inactive Anon", base::IntToString(meminfo.inactive_anon / 1024)));
  output.append(AddStringRow(
      "Shared", base::IntToString(meminfo.shmem / 1024)));
  output.append(AddStringRow(
      "Graphics", base::IntToString(meminfo.gem_size / 1024 / 1024)));
  output.append("</table>");

  AppendFooter(&output);
  return output;
}

#endif  // OS_CHROMEOS

// AboutDnsHandler bounces the request back to the IO thread to collect
// the DNS information.
class AboutDnsHandler : public base::RefCountedThreadSafe<AboutDnsHandler> {
 public:
  static void Start(Profile* profile,
                    const content::URLDataSource::GotDataCallback& callback) {
    scoped_refptr<AboutDnsHandler> handler(
        new AboutDnsHandler(profile, callback));
    handler->StartOnUIThread();
  }

 private:
  friend class base::RefCountedThreadSafe<AboutDnsHandler>;

  AboutDnsHandler(Profile* profile,
                  const content::URLDataSource::GotDataCallback& callback)
      : profile_(profile),
        callback_(callback) {
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
  }

  virtual ~AboutDnsHandler() {}

  // Calls FinishOnUIThread() on completion.
  void StartOnUIThread() {
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
    chrome_browser_net::Predictor* predictor = profile_->GetNetworkPredictor();
    BrowserThread::PostTask(
        BrowserThread::IO, FROM_HERE,
        base::Bind(&AboutDnsHandler::StartOnIOThread, this, predictor));
  }

  void StartOnIOThread(chrome_browser_net::Predictor* predictor) {
    DCHECK_CURRENTLY_ON(BrowserThread::IO);

    std::string data;
    AppendHeader(&data, 0, "About DNS");
    AppendBody(&data);
    chrome_browser_net::Predictor::PredictorGetHtmlInfo(predictor, &data);
    AppendFooter(&data);

    BrowserThread::PostTask(
        BrowserThread::UI, FROM_HERE,
        base::Bind(&AboutDnsHandler::FinishOnUIThread, this, data));
  }

  void FinishOnUIThread(const std::string& data) {
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
    std::string data_copy(data);
    callback_.Run(base::RefCountedString::TakeString(&data_copy));
  }

  Profile* profile_;

  // Callback to run with the response.
  content::URLDataSource::GotDataCallback callback_;

  DISALLOW_COPY_AND_ASSIGN(AboutDnsHandler);
};

void FinishMemoryDataRequest(
    const std::string& path,
    const content::URLDataSource::GotDataCallback& callback) {
  if (path == kStringsJsPath) {
    // The AboutMemoryHandler cleans itself up, but |StartFetch()| will want
    // the refcount to be greater than 0.
    scoped_refptr<AboutMemoryHandler> handler(new AboutMemoryHandler(callback));
    // TODO(jamescook): Maybe this shouldn't update UMA?
    handler->StartFetch(MemoryDetails::UPDATE_USER_METRICS);
  } else {
    int id = IDR_ABOUT_MEMORY_HTML;
    if (path == kMemoryJsPath) {
      id = IDR_ABOUT_MEMORY_JS;
    } else if (path == kMemoryCssPath) {
      id = IDR_ABOUT_MEMORY_CSS;
    }

    std::string result =
        ResourceBundle::GetSharedInstance().GetRawDataResource(id).as_string();
    callback.Run(base::RefCountedString::TakeString(&result));
  }
}

// Handler for filling in the "about:stats" page, as called by the browser's
// About handler processing.
// |query| is roughly the query string of the about:stats URL.
// Returns a string containing the HTML to render for the about:stats page.
// Conditional Output:
//      if |query| is "json", returns a JSON format of all counters.
//      if |query| is "raw", returns plain text of counter deltas.
//      otherwise, returns HTML with pretty JS/HTML to display the data.
std::string AboutStats(const std::string& query) {
  // We keep the base::DictionaryValue tree live so that we can do delta
  // stats computations across runs.
  CR_DEFINE_STATIC_LOCAL(base::DictionaryValue, root, ());
  static base::TimeTicks last_sample_time = base::TimeTicks::Now();

  base::TimeTicks now = base::TimeTicks::Now();
  base::TimeDelta time_since_last_sample = now - last_sample_time;
  last_sample_time = now;

  base::StatsTable* table = base::StatsTable::current();
  if (!table)
    return std::string();

  // We maintain two lists - one for counters and one for timers.
  // Timers actually get stored on both lists.
  base::ListValue* counters;
  if (!root.GetList("counters", &counters)) {
    counters = new base::ListValue();
    root.Set("counters", counters);
  }

  base::ListValue* timers;
  if (!root.GetList("timers", &timers)) {
    timers = new base::ListValue();
    root.Set("timers", timers);
  }

  // NOTE: Counters start at index 1.
  for (int index = 1; index <= table->GetMaxCounters(); index++) {
    // Get the counter's full name
    std::string full_name = table->GetRowName(index);
    if (full_name.length() == 0)
      break;
    DCHECK_EQ(':', full_name[1]);
    char counter_type = full_name[0];
    std::string name = full_name.substr(2);

    // JSON doesn't allow '.' in names.
    size_t pos;
    while ((pos = name.find(".")) != std::string::npos)
      name.replace(pos, 1, ":");

    // Try to see if this name already exists.
    base::DictionaryValue* counter = NULL;
    for (size_t scan_index = 0;
         scan_index < counters->GetSize(); scan_index++) {
      base::DictionaryValue* dictionary;
      if (counters->GetDictionary(scan_index, &dictionary)) {
        std::string scan_name;
        if (dictionary->GetString("name", &scan_name) && scan_name == name) {
          counter = dictionary;
        }
      } else {
        NOTREACHED();  // Should always be there
      }
    }

    if (counter == NULL) {
      counter = new base::DictionaryValue();
      counter->SetString("name", name);
      counters->Append(counter);
    }

    switch (counter_type) {
      case 'c':
        {
          int new_value = table->GetRowValue(index);
          int prior_value = 0;
          int delta = 0;
          if (counter->GetInteger("value", &prior_value)) {
            delta = new_value - prior_value;
          }
          counter->SetInteger("value", new_value);
          counter->SetInteger("delta", delta);
        }
        break;
      case 'm':
        {
          // TODO(mbelshe): implement me.
        }
        break;
      case 't':
        {
          int time = table->GetRowValue(index);
          counter->SetInteger("time", time);

          // Store this on the timers list as well.
          timers->Append(counter);
        }
        break;
      default:
        NOTREACHED();
    }
  }

  std::string data;
  if (query == "json" || query == kStringsJsPath) {
    base::JSONWriter::WriteWithOptions(
          &root,
          base::JSONWriter::OPTIONS_PRETTY_PRINT,
          &data);
    if (query == kStringsJsPath)
      data = "var templateData = " + data + ";";
  } else if (query == "raw") {
    // Dump the raw counters which have changed in text format.
    data = "<pre>";
    data.append(base::StringPrintf("Counter changes in the last %ldms\n",
        static_cast<long int>(time_since_last_sample.InMilliseconds())));
    for (size_t i = 0; i < counters->GetSize(); ++i) {
      base::Value* entry = NULL;
      bool rv = counters->Get(i, &entry);
      if (!rv)
        continue;  // None of these should fail.
      base::DictionaryValue* counter =
          static_cast<base::DictionaryValue*>(entry);
      int delta;
      rv = counter->GetInteger("delta", &delta);
      if (!rv)
        continue;
      if (delta > 0) {
        std::string name;
        rv = counter->GetString("name", &name);
        if (!rv)
          continue;
        int value;
        rv = counter->GetInteger("value", &value);
        if (!rv)
          continue;
        data.append(name);
        data.append(":");
        data.append(base::IntToString(delta));
        data.append("\n");
      }
    }
    data.append("</pre>");
  } else {
    // Get about_stats.html/js from resource bundle.
    data = ResourceBundle::GetSharedInstance().GetRawDataResource(
        (query == kStatsJsPath ?
         IDR_ABOUT_STATS_JS : IDR_ABOUT_STATS_HTML)).as_string();

    if (query != kStatsJsPath) {
      // Clear the timer list since we stored the data in the timers list
      // as well.
      for (int index = static_cast<int>(timers->GetSize())-1; index >= 0;
           index--) {
        scoped_ptr<base::Value> value;
        timers->Remove(index, &value);
        // We don't care about the value pointer; it's still tracked
        // on the counters list.
        ignore_result(value.release());
      }
    }
  }

  return data;
}

#if defined(OS_LINUX) || defined(OS_OPENBSD)
std::string AboutLinuxProxyConfig() {
  std::string data;
  AppendHeader(&data, 0,
               l10n_util::GetStringUTF8(IDS_ABOUT_LINUX_PROXY_CONFIG_TITLE));
  data.append("<style>body { max-width: 70ex; padding: 2ex 5ex; }</style>");
  AppendBody(&data);
  base::FilePath binary = CommandLine::ForCurrentProcess()->GetProgram();
  data.append(l10n_util::GetStringFUTF8(
      IDS_ABOUT_LINUX_PROXY_CONFIG_BODY,
      l10n_util::GetStringUTF16(IDS_PRODUCT_NAME),
      base::ASCIIToUTF16(binary.BaseName().value())));
  AppendFooter(&data);
  return data;
}

void AboutSandboxRow(std::string* data, const std::string& prefix, int name_id,
                     bool good) {
  data->append("<tr><td>");
  data->append(prefix);
  data->append(l10n_util::GetStringUTF8(name_id));
  if (good) {
    data->append("</td><td style='color: green;'>");
    data->append(
        l10n_util::GetStringUTF8(IDS_CONFIRM_MESSAGEBOX_YES_BUTTON_LABEL));
  } else {
    data->append("</td><td style='color: red;'>");
    data->append(
        l10n_util::GetStringUTF8(IDS_CONFIRM_MESSAGEBOX_NO_BUTTON_LABEL));
  }
  data->append("</td></tr>");
}

std::string AboutSandbox() {
  std::string data;
  AppendHeader(&data, 0, l10n_util::GetStringUTF8(IDS_ABOUT_SANDBOX_TITLE));
  AppendBody(&data);
  data.append("<h1>");
  data.append(l10n_util::GetStringUTF8(IDS_ABOUT_SANDBOX_TITLE));
  data.append("</h1>");

  // Get expected sandboxing status of renderers.
  const int status = content::ZygoteHost::GetInstance()->GetSandboxStatus();

  data.append("<table>");

  AboutSandboxRow(&data,
                  std::string(),
                  IDS_ABOUT_SANDBOX_SUID_SANDBOX,
                  status & content::kSandboxLinuxSUID);
  AboutSandboxRow(&data, "&nbsp;&nbsp;", IDS_ABOUT_SANDBOX_PID_NAMESPACES,
                  status & content::kSandboxLinuxPIDNS);
  AboutSandboxRow(&data, "&nbsp;&nbsp;", IDS_ABOUT_SANDBOX_NET_NAMESPACES,
                  status & content::kSandboxLinuxNetNS);
  AboutSandboxRow(&data,
                  std::string(),
                  IDS_ABOUT_SANDBOX_SECCOMP_BPF_SANDBOX,
                  status & content::kSandboxLinuxSeccompBPF);
  AboutSandboxRow(&data,
                  std::string(),
                  IDS_ABOUT_SANDBOX_YAMA_LSM,
                  status & content::kSandboxLinuxYama);

  data.append("</table>");

  // The setuid sandbox is required as our first-layer sandbox.
  bool good_layer1 = status & content::kSandboxLinuxSUID &&
                     status & content::kSandboxLinuxPIDNS &&
                     status & content::kSandboxLinuxNetNS;
  // A second-layer sandbox is also required to be adequately sandboxed.
  bool good_layer2 = status & content::kSandboxLinuxSeccompBPF;
  bool good = good_layer1 && good_layer2;

  if (good) {
    data.append("<p style='color: green'>");
    data.append(l10n_util::GetStringUTF8(IDS_ABOUT_SANDBOX_OK));
  } else {
    data.append("<p style='color: red'>");
    data.append(l10n_util::GetStringUTF8(IDS_ABOUT_SANDBOX_BAD));
  }
  data.append("</p>");

  AppendFooter(&data);
  return data;
}
#endif

// AboutMemoryHandler ----------------------------------------------------------

// Helper for AboutMemory to bind results from a ProcessMetrics object
// to a DictionaryValue. Fills ws_usage and comm_usage so that the objects
// can be used in caller's scope (e.g for appending to a net total).
void AboutMemoryHandler::BindProcessMetrics(base::DictionaryValue* data,
                                            ProcessMemoryInformation* info) {
  DCHECK(data && info);

  // Bind metrics to dictionary.
  data->SetInteger("ws_priv", static_cast<int>(info->working_set.priv));
  data->SetInteger("ws_shareable",
    static_cast<int>(info->working_set.shareable));
  data->SetInteger("ws_shared", static_cast<int>(info->working_set.shared));
  data->SetInteger("comm_priv", static_cast<int>(info->committed.priv));
  data->SetInteger("comm_map", static_cast<int>(info->committed.mapped));
  data->SetInteger("comm_image", static_cast<int>(info->committed.image));
  data->SetInteger("pid", info->pid);
  data->SetString("version", info->version);
  data->SetInteger("processes", info->num_processes);
}

// Helper for AboutMemory to append memory usage information for all
// sub-processes (i.e. renderers, plugins) used by Chrome.
void AboutMemoryHandler::AppendProcess(base::ListValue* child_data,
                                       ProcessMemoryInformation* info) {
  DCHECK(child_data && info);

  // Append a new DictionaryValue for this renderer to our list.
  base::DictionaryValue* child = new base::DictionaryValue();
  child_data->Append(child);
  BindProcessMetrics(child, info);

  std::string child_label(
      ProcessMemoryInformation::GetFullTypeNameInEnglish(info->process_type,
                                                         info->renderer_type));
  if (info->is_diagnostics)
    child_label.append(" (diagnostics)");
  child->SetString("child_name", child_label);
  base::ListValue* titles = new base::ListValue();
  child->Set("titles", titles);
  for (size_t i = 0; i < info->titles.size(); ++i)
    titles->Append(new base::StringValue(info->titles[i]));
}

void AboutMemoryHandler::OnDetailsAvailable() {
  // the root of the JSON hierarchy for about:memory jstemplate
  scoped_ptr<base::DictionaryValue> root(new base::DictionaryValue);
  base::ListValue* browsers = new base::ListValue();
  root->Set("browsers", browsers);

  const std::vector<ProcessData>& browser_processes = processes();

  // Aggregate per-process data into browser summary data.
  base::string16 log_string;
  for (size_t index = 0; index < browser_processes.size(); index++) {
    if (browser_processes[index].processes.empty())
      continue;

    // Sum the information for the processes within this browser.
    ProcessMemoryInformation aggregate;
    ProcessMemoryInformationList::const_iterator iterator;
    iterator = browser_processes[index].processes.begin();
    aggregate.pid = iterator->pid;
    aggregate.version = iterator->version;
    while (iterator != browser_processes[index].processes.end()) {
      if (!iterator->is_diagnostics ||
          browser_processes[index].processes.size() == 1) {
        aggregate.working_set.priv += iterator->working_set.priv;
        aggregate.working_set.shared += iterator->working_set.shared;
        aggregate.working_set.shareable += iterator->working_set.shareable;
        aggregate.committed.priv += iterator->committed.priv;
        aggregate.committed.mapped += iterator->committed.mapped;
        aggregate.committed.image += iterator->committed.image;
        aggregate.num_processes++;
      }
      ++iterator;
    }
    base::DictionaryValue* browser_data = new base::DictionaryValue();
    browsers->Append(browser_data);
    browser_data->SetString("name", browser_processes[index].name);

    BindProcessMetrics(browser_data, &aggregate);

    // We log memory info as we record it.
    if (!log_string.empty())
      log_string += base::ASCIIToUTF16(", ");
    log_string += browser_processes[index].name + base::ASCIIToUTF16(", ") +
                  base::Int64ToString16(aggregate.working_set.priv) +
                  base::ASCIIToUTF16(", ") +
                  base::Int64ToString16(aggregate.working_set.shared) +
                  base::ASCIIToUTF16(", ") +
                  base::Int64ToString16(aggregate.working_set.shareable);
  }
  if (!log_string.empty())
    VLOG(1) << "memory: " << log_string;

  // Set the browser & renderer detailed process data.
  base::DictionaryValue* browser_data = new base::DictionaryValue();
  root->Set("browzr_data", browser_data);
  base::ListValue* child_data = new base::ListValue();
  root->Set("child_data", child_data);

  ProcessData process = browser_processes[0];  // Chrome is the first browser.
  root->SetString("current_browser_name", process.name);

  for (size_t index = 0; index < process.processes.size(); index++) {
    if (process.processes[index].process_type == content::PROCESS_TYPE_BROWSER)
      BindProcessMetrics(browser_data, &process.processes[index]);
    else
      AppendProcess(child_data, &process.processes[index]);
  }

  root->SetBoolean("show_other_browsers",
      browser_defaults::kShowOtherBrowsersInAboutMemory);

  base::DictionaryValue load_time_data;
  load_time_data.SetString(
      "summary_desc",
      l10n_util::GetStringUTF16(IDS_MEMORY_USAGE_SUMMARY_DESC));
  webui::SetFontAndTextDirection(&load_time_data);
  load_time_data.Set("jstemplateData", root.release());

  webui::UseVersion2 version2;
  std::string data;
  webui::AppendJsonJS(&load_time_data, &data);
  callback_.Run(base::RefCountedString::TakeString(&data));
}

}  // namespace

// AboutUIHTMLSource ----------------------------------------------------------

AboutUIHTMLSource::AboutUIHTMLSource(const std::string& source_name,
                                     Profile* profile)
    : source_name_(source_name),
      profile_(profile) {}

AboutUIHTMLSource::~AboutUIHTMLSource() {}

std::string AboutUIHTMLSource::GetSource() const {
  return source_name_;
}

void AboutUIHTMLSource::StartDataRequest(
    const std::string& path,
    int render_process_id,
    int render_frame_id,
    const content::URLDataSource::GotDataCallback& callback) {
  std::string response;
  // Add your data source here, in alphabetical order.
  if (source_name_ == chrome::kChromeUIChromeURLsHost) {
    response = ChromeURLs();
  } else if (source_name_ == chrome::kChromeUICreditsHost) {
    int idr = (path == kCreditsJsPath) ? IDR_CREDITS_JS : IDR_CREDITS_HTML;
    response = ResourceBundle::GetSharedInstance().GetRawDataResource(
        idr).as_string();
#if defined(OS_CHROMEOS)
  } else if (source_name_ == chrome::kChromeUIDiscardsHost) {
    response = AboutDiscards(path);
#endif
  } else if (source_name_ == chrome::kChromeUIDNSHost) {
    AboutDnsHandler::Start(profile(), callback);
    return;
#if defined(OS_LINUX) || defined(OS_OPENBSD)
  } else if (source_name_ == chrome::kChromeUILinuxProxyConfigHost) {
    response = AboutLinuxProxyConfig();
#endif
  } else if (source_name_ == chrome::kChromeUIMemoryHost) {
    response = GetAboutMemoryRedirectResponse(profile());
  } else if (source_name_ == chrome::kChromeUIMemoryRedirectHost) {
    FinishMemoryDataRequest(path, callback);
    return;
#if defined(OS_CHROMEOS)
  } else if (source_name_ == chrome::kChromeUIOSCreditsHost) {
    response = ResourceBundle::GetSharedInstance().GetRawDataResource(
        IDR_OS_CREDITS_HTML).as_string();
#endif
#if defined(OS_LINUX) || defined(OS_OPENBSD)
  } else if (source_name_ == chrome::kChromeUISandboxHost) {
    response = AboutSandbox();
#endif
  } else if (source_name_ == chrome::kChromeUIStatsHost) {
    response = AboutStats(path);
  } else if (source_name_ == chrome::kChromeUITermsHost) {
#if defined(OS_CHROMEOS)
    ChromeOSTermsHandler::Start(path, callback);
    return;
#else
    response = l10n_util::GetStringUTF8(IDS_TERMS_HTML);
#endif
  }

  FinishDataRequest(response, callback);
}

void AboutUIHTMLSource::FinishDataRequest(
    const std::string& html,
    const content::URLDataSource::GotDataCallback& callback) {
  std::string html_copy(html);
  callback.Run(base::RefCountedString::TakeString(&html_copy));
}

std::string AboutUIHTMLSource::GetMimeType(const std::string& path) const {
  if (path == kCreditsJsPath ||
      path == kStatsJsPath   ||
      path == kStringsJsPath ||
      path == kMemoryJsPath) {
    return "application/javascript";
  }
  return "text/html";
}

bool AboutUIHTMLSource::ShouldAddContentSecurityPolicy() const {
#if defined(OS_CHROMEOS)
  if (source_name_ == chrome::kChromeUIOSCreditsHost)
    return false;
#endif
  return content::URLDataSource::ShouldAddContentSecurityPolicy();
}

bool AboutUIHTMLSource::ShouldDenyXFrameOptions() const {
#if defined(OS_CHROMEOS)
  if (source_name_ == chrome::kChromeUITermsHost) {
    // chrome://terms page is embedded in iframe to chrome://oobe.
    return false;
  }
#endif
  return content::URLDataSource::ShouldDenyXFrameOptions();
}

AboutUI::AboutUI(content::WebUI* web_ui, const std::string& name)
    : WebUIController(web_ui) {
  Profile* profile = Profile::FromWebUI(web_ui);

#if defined(ENABLE_THEMES)
  // Set up the chrome://theme/ source.
  ThemeSource* theme = new ThemeSource(profile);
  content::URLDataSource::Add(profile, theme);
#endif

  content::URLDataSource::Add(profile, new AboutUIHTMLSource(name, profile));
}