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>
 
@@ skipping 1430 matching lines @@
   WebContents* web_contents = WebContents::FromRenderViewHost(rvh);
   chrome::ViewType view_type = chrome::GetViewType(web_contents);
   ExtensionService* service = profile->GetExtensionService();
   if (service) {
     const Extension* extension = service->extensions()->GetByID(
         rvh->GetSiteInstance()->GetSite().host());
     extension_webkit_preferences::SetPreferences(
         extension, view_type, web_prefs);
   }
 
+  if (chrome_browser_trials::g_in_force_compositing_mode_trial)
+    web_prefs->force_compositing_mode = true;
+
   if (view_type == chrome::VIEW_TYPE_NOTIFICATION) {
     web_prefs->allow_scripts_to_close_windows = true;
   } else if (view_type == chrome::VIEW_TYPE_BACKGROUND_CONTENTS) {
     // Disable all kinds of acceleration for background pages.
     // See http://crbug.com/96005 and http://crbug.com/96006
     web_prefs->force_compositing_mode = false;
     web_prefs->accelerated_compositing_enabled = false;
     web_prefs->accelerated_2d_canvas_enabled = false;
     web_prefs->accelerated_video_enabled = false;
     web_prefs->accelerated_painting_enabled = false;
@@ skipping 158 matching lines @@
 #if defined(USE_NSS)
 crypto::CryptoModuleBlockingPasswordDelegate*
     ChromeContentBrowserClient::GetCryptoPasswordDelegate(
         const GURL& url) {
   return browser::NewCryptoModuleBlockingDialogDelegate(
       browser::kCryptoModulePasswordKeygen, url.host());
 }
 #endif
 
 }  // namespace chrome