SetInstallSignature  557 chrome/browser/extensions/install_verifier.cc     prefs_->SetInstallSignature(NULL);
SetInstallSignature  569 chrome/browser/extensions/install_verifier.cc     prefs_->SetInstallSignature(&pref);
SetInstallSignature  540 extensions/browser/extension_prefs.h   void SetInstallSignature(const base::DictionaryValue* signature);