WebPageVisibilityStateHidden  549 Source/web/AssertMatchingEnums.cpp COMPILE_ASSERT_MATCHING_ENUM(WebPageVisibilityStateHidden, PageVisibilityStateHidden);
WebPageVisibilityStateHidden 3921 Source/web/WebViewImpl.cpp     ASSERT(visibilityState == WebPageVisibilityStateVisible || visibilityState == WebPageVisibilityStateHidden || visibilityState == WebPageVisibilityStatePrerender);