Use GPU blacklist to control accelerated video decode.

content/renderer/render_view_impl.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 "content/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <string>
 #include <vector>
@@ skipping 2378 matching lines @@
     // from the perspective of the audio renderer.
     audio_source_provider = new RenderAudioSourceProvider();
 
     // Add the chrome specific audio renderer, using audio_source_provider
     // as the sink.
     media::AudioRendererImpl* audio_renderer =
         new media::AudioRendererImpl(audio_source_provider);
     collection->AddAudioRenderer(audio_renderer);
   }
 
-  // Accelerated video decode is not enabled by default on Linux.
-  // crbug.com/137247
-  bool use_accelerated_video_decode = false;
-#if defined(OS_CHROMEOS)
-  use_accelerated_video_decode = true;
-#endif
-  use_accelerated_video_decode &= !CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kDisableAcceleratedVideoDecode);
-  WebGraphicsContext3DCommandBufferImpl* context3d =
-      use_accelerated_video_decode ?
-      RenderThreadImpl::current()->GetGpuVDAContext3D() :
-      NULL;
-  if (context3d) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableAcceleratedVideoDecode)) {
+    WebGraphicsContext3DCommandBufferImpl* context3d =

[Ami GONE FROM CHROMIUM, 2012/08/17 17:51:03]

You went too far :)
context3d may still be NULL after this line runs, b/c of failure to create
contexts or spawn GPU process or whatnot.
(hence my previously suggested form)

[Zhenyao Mo, 2012/08/17 20:08:17]

Ah thanks for catching the bug.  Fixed.

+        RenderThreadImpl::current()->GetGpuVDAContext3D();
     scoped_refptr<base::MessageLoopProxy> factories_loop =
         RenderThreadImpl::current()->compositor_thread() ?
         RenderThreadImpl::current()->compositor_thread()->GetWebThread()
             ->message_loop()->message_loop_proxy() :
         base::MessageLoopProxy::current();
     GpuChannelHost* gpu_channel_host =
         RenderThreadImpl::current()->EstablishGpuChannelSync(
             content::CAUSE_FOR_GPU_LAUNCH_VIDEODECODEACCELERATOR_INITIALIZE);
     collection->GetVideoDecoders()->push_back(new media::GpuVideoDecoder(
         base::Bind(&media::MessageLoopFactory::GetMessageLoop,
@@ skipping 3373 matching lines @@
 bool RenderViewImpl::WebWidgetHandlesCompositorScheduling() const {
   return !!RenderThreadImpl::current()->compositor_thread();
 }
 
 void RenderViewImpl::OnJavaBridgeInit() {
   DCHECK(!java_bridge_dispatcher_);
 #if defined(ENABLE_JAVA_BRIDGE)
   java_bridge_dispatcher_ = new JavaBridgeDispatcher(this);
 #endif
 }