Adding a field trial for testing --force-compositing-mode on 50% of

chrome/browser/chrome_content_browser_client.cc

 // 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/chrome_content_browser_client.h"
 
 #include <set>
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
+#include "base/metrics/histogram.h"
 #include "base/string_tokenizer.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/app/breakpad_mac.h"
 #include "chrome/browser/browser_about_handler.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/browser_trial.h"
 #include "chrome/browser/browsing_data_helper.h"
 #include "chrome/browser/browsing_data_remover.h"
 #include "chrome/browser/character_encoding.h"
 #include "chrome/browser/chrome_benchmarking_message_filter.h"
 #include "chrome/browser/chrome_quota_permission_context.h"
 #include "chrome/browser/content_settings/content_settings_utils.h"
 #include "chrome/browser/content_settings/cookie_settings.h"
 #include "chrome/browser/content_settings/host_content_settings_map.h"
 #include "chrome/browser/content_settings/tab_specific_content_settings.h"
 #include "chrome/browser/defaults.h"
@@ skipping 40 matching lines @@
 #include "chrome/browser/ui/media_stream_infobar_delegate.h"
 #include "chrome/browser/ui/tab_contents/chrome_web_contents_view_delegate.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
 #include "chrome/browser/ui/webui/chrome_web_ui_controller_factory.h"
 #include "chrome/browser/user_style_sheet_watcher.h"
 #include "chrome/browser/user_style_sheet_watcher_factory.h"
 #include "chrome/browser/view_type_utils.h"
 #include "chrome/common/child_process_logging.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
+#include "chrome/common/chrome_version_info.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_process_policy.h"
 #include "chrome/common/extensions/extension_set.h"
 #include "chrome/common/logging_chrome.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/browser_child_process_host.h"
 #include "content/public/browser/browser_main_parts.h"
 #include "content/public/browser/browser_url_handler.h"
 #include "content/public/browser/child_process_security_policy.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/resource_context.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_view.h"
 #include "content/public/common/child_process_host.h"
 #include "grit/generated_resources.h"
 #include "grit/ui_resources.h"
 #include "net/base/ssl_cert_request_info.h"
 #include "net/cookies/cookie_monster.h"
 #include "net/cookies/cookie_options.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "webkit/glue/webpreferences.h"
 #include "webkit/plugins/plugin_switches.h"
 
 #if defined(OS_WIN)
+#include "base/win/windows_version.h"
 #include "chrome/browser/chrome_browser_main_win.h"
 #elif defined(OS_MACOSX)
+#include "base/mac/mac_util.h"
 #include "chrome/browser/chrome_browser_main_mac.h"
 #include "chrome/browser/spellchecker/spellcheck_message_filter_mac.h"
 #elif defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/chrome_browser_main_chromeos.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #elif defined(OS_LINUX)
 #include "chrome/browser/chrome_browser_main_linux.h"
 #elif defined(OS_POSIX)
 #include "chrome/browser/chrome_browser_main_posix.h"
 #endif
@@ skipping 181 matching lines @@
                        WebPreferences::ScriptFontFamilyMap* map) {
   for (size_t i = 0; i < prefs::kWebKitScriptsForFontFamilyMapsLength; ++i) {
     const char* script = prefs::kWebKitScriptsForFontFamilyMaps[i];
     std::string pref_name = base::StringPrintf("%s.%s", map_name, script);
     std::string font_family = prefs->GetString(pref_name.c_str());
     if (!font_family.empty())
       (*map)[script] = UTF8ToUTF16(font_family);
   }
 }
 
+void CheckForceCompositingModeTrialFlag(CommandLine* command_line) {
+  chrome::VersionInfo::Channel channel = chrome::VersionInfo::GetChannel();
+  // Only run the trial on the Canary channel.
+  if (channel != chrome::VersionInfo::CHANNEL_CANARY)
+    return;
+#if defined(OS_WIN)
+  // Don't run the trial on windows XP.
+  if (base::win::GetVersion() < base::win::VERSION_VISTA)
+    return;
+#elif defined(OS_MACOSX)
+  // Accelerated compositing is only implemented on Mac OSX 10.6 or later.
+  if (base::mac::IsOSLeopardOrEarlier())
+    return;
+#endif
+
+  static base::FieldTrial* trial = NULL;
+  static bool in_enable_group = false;
+
+  if (!trial) {
+    const base::FieldTrial::Probability kDivisor = 100;
+    // 50% probability of being in the enabled group.
+    const base::FieldTrial::Probability kEnableProbability = 50;
+    trial = base::FieldTrialList::FactoryGetFieldTrial(
+        BrowserTrial::kForceCompositingModeTrial, kDivisor,
+        "disable", 2012, 12, 31, NULL);
+    // Produce the same result on every run of this client.
+    trial->UseOneTimeRandomization();
+    int enable_group = trial->AppendGroup("enable", kEnableProbability);
+    in_enable_group = (trial->group() == enable_group);
+    UMA_HISTOGRAM_ENUMERATION("GPU.InForceCompositingModeFieldTrial",

[Ilya Sherman, 2012/06/06 09:50:21]

nit: UMA_HISTOGRAM_BOOLEAN?

+                              in_enable_group ? 1 : 0, 2);
+  }
+
+  if (in_enable_group)
+    command_line->AppendSwitch(switches::kForceCompositingMode);
+}
+
 }  // namespace
 
 namespace chrome {
 
 ChromeContentBrowserClient::ChromeContentBrowserClient() {
   for (size_t i = 0; i < arraysize(kPredefinedAllowedSocketOrigins); ++i)
     allowed_socket_origins_.insert(kPredefinedAllowedSocketOrigins[i]);
 }
 
 ChromeContentBrowserClient::~ChromeContentBrowserClient() {
@@ skipping 424 matching lines @@
       }
     }
     {
       PrefService* local_state = g_browser_process->local_state();
       if (local_state &&
           !local_state->GetBoolean(prefs::kPrintPreviewDisabled)) {
         command_line->AppendSwitch(switches::kRendererPrintPreview);
       }
     }
 
+    CheckForceCompositingModeTrialFlag(command_line);
+
     // Please keep this in alphabetical order.
     static const char* const kSwitchNames[] = {
       switches::kAllowHTTPBackgroundPage,
       switches::kAllowLegacyExtensionManifests,
       switches::kAllowScriptingGallery,
       switches::kAppsCheckoutURL,
       switches::kAppsGalleryURL,
       switches::kCloudPrintServiceURL,
       switches::kDebugPrint,
       switches::kDisableAsynchronousSpellChecking,
@@ skipping 855 matching lines @@
 #if defined(USE_NSS)
 crypto::CryptoModuleBlockingPasswordDelegate*
     ChromeContentBrowserClient::GetCryptoPasswordDelegate(
         const GURL& url) {
   return browser::NewCryptoModuleBlockingDialogDelegate(
       browser::kCryptoModulePasswordKeygen, url.host());
 }
 #endif
 
 }  // namespace chrome