Move a bunch of content\common code into the content namespace.

content/common/gpu/media/rendering_helper.h

Index: content/common/gpu/media/rendering_helper.h
===================================================================
--- content/common/gpu/media/rendering_helper.h	(revision 163460)
+++ content/common/gpu/media/rendering_helper.h	(working copy)
@@ -11,7 +11,7 @@
 class WaitableEvent;
 }
 
-namespace video_test_util {
+namespace content {
 
 // Creates and draws textures used by the video decoder.
 // This class is not thread safe and thus all the methods of this class
@@ -57,6 +57,6 @@
   virtual void* GetGLDisplay() = 0;
 };
 
-}  // namespace video_test_util
+}  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_MEDIA_RENDERING_HELPER_H_