Use GPU blacklist to control accelerated video decode.

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
===================================================================
--- content/renderer/render_view_impl.cc	(revision 151736)
+++ content/renderer/render_view_impl.cc	(working copy)
@@ -2396,19 +2396,10 @@
     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()