Move a bunch of code in content\common (as well as a few left in renderer) to the content namespace.

content/renderer/media/renderer_gpu_video_decoder_factories.h

Index: content/renderer/media/renderer_gpu_video_decoder_factories.h
===================================================================
--- content/renderer/media/renderer_gpu_video_decoder_factories.h	(revision 163290)
+++ content/renderer/media/renderer_gpu_video_decoder_factories.h	(working copy)
@@ -12,14 +12,13 @@
 #include "media/filters/gpu_video_decoder.h"
 #include "ui/gfx/size.h"
 
-class ContentGLContext;
-class GpuChannelHost;
-class WebGraphicsContext3DCommandBufferImpl;
 namespace base {
 class WaitableEvent;
 }
 
 namespace content {
+class GpuChannelHost;
+class WebGraphicsContext3DCommandBufferImpl;
 
 // Glue code to expose functionality needed by media::GpuVideoDecoder to
 // RenderViewImpl.  This class is entirely an implementation detail of