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

content/common/gpu/image_transport_surface.h

Index: content/common/gpu/image_transport_surface.h
===================================================================
--- content/common/gpu/image_transport_surface.h	(revision 163290)
+++ content/common/gpu/image_transport_surface.h	(working copy)
@@ -22,9 +22,6 @@
 #include "ui/gl/gl_surface.h"
 #include "ui/surface/transport_dib.h"
 
-class GpuChannelManager;
-class GpuCommandBufferStub;
-
 struct GpuHostMsg_AcceleratedSurfaceNew_Params;
 struct GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params;
 struct GpuHostMsg_AcceleratedSurfacePostSubBuffer_Params;
@@ -42,6 +39,10 @@
 }
 }
 
+namespace content {
+class GpuChannelManager;
+class GpuCommandBufferStub;
+
 // The GPU process is agnostic as to how it displays results. On some platforms
 // it renders directly to window. On others it renders offscreen and transports
 // the results to the browser process to display. This file provides a simple
@@ -193,6 +194,8 @@
   DISALLOW_COPY_AND_ASSIGN(PassThroughImageTransportSurface);
 };
 
+}  // namespace content
+
 #endif  // defined(ENABLE_GPU)
 
 #endif  // CONTENT_COMMON_GPU_IMAGE_TRANSPORT_SURFACE_H_