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

content/browser/gpu/gpu_data_manager.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 "content/browser/gpu/gpu_data_manager.h"
 
 #if defined(OS_MACOSX)
 #include <CoreGraphics/CGDisplayConfiguration.h>
 #endif
 
@@ skipping 130 matching lines @@
       entry_index += 2;
       break;
   }
   return entry_index;
 }
 #endif  // OS_WIN
 
 }  // namespace anonymous
 
 GpuDataManager::UserFlags::UserFlags()
-    : disable_accelerated_2d_canvas_(false),
+    : disable_accelerated_2d_canvas_(true),
       disable_accelerated_compositing_(false),
       disable_accelerated_layers_(false),
       disable_experimental_webgl_(false),
       disable_gl_multisampling_(false),
       ignore_gpu_blacklist_(false) {
 }
 
 void GpuDataManager::UserFlags::Initialize() {
   const CommandLine& browser_command_line =
       *CommandLine::ForCurrentProcess();
 
-  disable_accelerated_2d_canvas_ = browser_command_line.HasSwitch(
-      switches::kDisableAccelerated2dCanvas);
+  disable_accelerated_2d_canvas_ = !browser_command_line.HasSwitch(
+      switches::kEnableAccelerated2dCanvas);
   disable_accelerated_compositing_ = browser_command_line.HasSwitch(
       switches::kDisableAcceleratedCompositing);
   disable_accelerated_layers_ = browser_command_line.HasSwitch(
       switches::kDisableAcceleratedLayers);
   disable_experimental_webgl_ = browser_command_line.HasSwitch(
       switches::kDisableExperimentalWebGL);
   disable_gl_multisampling_ = browser_command_line.HasSwitch(
       switches::kDisableGLMultisampling);
 
   ignore_gpu_blacklist_ = browser_command_line.HasSwitch(
@@ skipping 84 matching lines @@
 
   uint32 flags = GetGpuFeatureFlags().flags();
   DictionaryValue* status = new DictionaryValue();
 
   const GpuFeatureInfo kGpuFeatureInfo[] = {
       {
           "2d_canvas",
           flags & GpuFeatureFlags::kGpuFeatureAccelerated2dCanvas,
           user_flags_.disable_accelerated_2d_canvas() ||
           !supportsAccelerated2dCanvas(),
-          "Accelerated 2D canvas is unavailable: either disabled at the command"
-          " line or not supported by the current system.",
+          "Accelerated 2D canvas is unavailable: either not enabled via"
+          " about:flags or not supported by the current system.",
           true
       },
       {
           "compositing",
           flags & GpuFeatureFlags::kGpuFeatureAcceleratedCompositing,
           user_flags_.disable_accelerated_compositing(),
           "Accelerated compositing has been disabled, either via about:flags or"
           " command line. This adversely affects performance of all hardware"
           " accelerated features.",
           true
@@ skipping 158 matching lines @@
       command_line->AppendSwitch(switches::kDisableExperimentalWebGL);
     if (!command_line->HasSwitch(switches::kDisablePepper3dForUntrustedUse))
       command_line->AppendSwitch(switches::kDisablePepper3dForUntrustedUse);
   }
   if ((flags & GpuFeatureFlags::kGpuFeatureMultisampling) &&
       !command_line->HasSwitch(switches::kDisableGLMultisampling))
     command_line->AppendSwitch(switches::kDisableGLMultisampling);
   if ((flags & GpuFeatureFlags::kGpuFeatureAcceleratedCompositing) &&
       !command_line->HasSwitch(switches::kDisableAcceleratedCompositing))
     command_line->AppendSwitch(switches::kDisableAcceleratedCompositing);
-  if ((flags & GpuFeatureFlags::kGpuFeatureAccelerated2dCanvas) &&
-      !command_line->HasSwitch(switches::kDisableAccelerated2dCanvas))
-    command_line->AppendSwitch(switches::kDisableAccelerated2dCanvas);
 }
 
 void GpuDataManager::AppendGpuCommandLine(
     CommandLine* command_line) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DCHECK(command_line);
 
   uint32 flags = gpu_feature_flags_.flags();
   if ((flags & GpuFeatureFlags::kGpuFeatureMultisampling) &&
       !command_line->HasSwitch(switches::kDisableGLMultisampling))
@@ skipping 241 matching lines @@
 bool GpuDataManager::supportsAccelerated2dCanvas() const {
   if (gpu_info_.can_lose_context)
     return false;
 #if defined(USE_SKIA)
   return true;
 #else
   return false;
 #endif
 }