Disable accelerated 2d canvas and put it back as an option in about:flags.

chrome/browser/about_flags.cc

 // Copyright (c) 2011 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/about_flags.h"
 
 #include <algorithm>
 #include <iterator>
 #include <map>
 #include <set>
@@ skipping 158 matching lines @@
     kOsAll,
     SINGLE_VALUE_TYPE(switches::kDisableGpuVsync)
   },
   {
     "disable-webgl",
     IDS_FLAGS_DISABLE_WEBGL_NAME,
     IDS_FLAGS_DISABLE_WEBGL_DESCRIPTION,
     kOsAll,
     SINGLE_VALUE_TYPE(switches::kDisableExperimentalWebGL)
   },
+  {
+    "gpu-canvas-2d",  // FLAGS:RECORD_UMA
+    IDS_FLAGS_ACCELERATED_CANVAS_2D_NAME,
+    IDS_FLAGS_ACCELERATED_CANVAS_2D_DESCRIPTION,
+    kOsWin | kOsLinux | kOsCrOS,
+    SINGLE_VALUE_TYPE(switches::kEnableAccelerated2dCanvas)
+  },
   // Exposed on all platforms until there is a workaround for easy access to
   // the native print dialog for users that need it. Once that's done, revert
   // back to:
   // Only expose this for Chromium builds where users may not have the PDF
   // plugin. Do not give Google Chrome users the option to disable it here.
   // Also expose it for Chrome OS where print preview is still experimental.
   {
     "print-preview",  // FLAGS:RECORD_UMA
     IDS_FLAGS_PRINT_PREVIEW_NAME,
     IDS_FLAGS_PRINT_PREVIEW_DESCRIPTION,
@@ skipping 635 matching lines @@
 }
 
 const Experiment* GetExperiments(size_t* count) {
   *count = num_experiments;
   return experiments;
 }
 
 }  // namespace testing
 
 }  // namespace about_flags