Move Mailbox from cc to gpu, and its traits to gpu/ipc

cc/gl_frame_data.h

Index: cc/gl_frame_data.h
diff --git a/cc/gl_frame_data.h b/cc/gl_frame_data.h
index 8d281e9f0c89ccc009ec9e37eafe357c28661edd..0951c28eb3bf9eceaa988fb0f684937b68209035 100644
--- a/cc/gl_frame_data.h
+++ b/cc/gl_frame_data.h
@@ -9,7 +9,7 @@
 
 #include "base/basictypes.h"
 #include "cc/cc_export.h"
-#include "cc/transferable_resource.h"
+#include "gpu/command_buffer/common/mailbox.h"
 #include "ui/gfx/size.h"
 
 namespace cc {
@@ -19,7 +19,7 @@ class CC_EXPORT GLFrameData {
   GLFrameData();
   ~GLFrameData();
 
-  Mailbox mailbox;
+  gpu::Mailbox mailbox;
   uint32 sync_point;
   gfx::Size size;
 };