Add multi-process GpuMemoryBuffer framework.

content/common/child_process_messages.h

Index: content/common/child_process_messages.h
diff --git a/content/common/child_process_messages.h b/content/common/child_process_messages.h
index 3f70bc38ab2fb623b6536b0455e2525ae92a3638..c12258862a391c6718cc419340a11117ce1de62d 100644
--- a/content/common/child_process_messages.h
+++ b/content/common/child_process_messages.h
@@ -13,6 +13,7 @@
 #include "base/values.h"
 #include "content/common/content_export.h"
 #include "ipc/ipc_message_macros.h"
+#include "ui/gfx/gpu_memory_buffer.h"
 
 IPC_ENUM_TRAITS(tracked_objects::ThreadData::Status)
 
@@ -54,6 +55,13 @@ IPC_STRUCT_TRAITS_BEGIN(tracked_objects::ProcessDataSnapshot)
   IPC_STRUCT_TRAITS_MEMBER(process_id)
 IPC_STRUCT_TRAITS_END()
 
+IPC_ENUM_TRAITS(gfx::GpuMemoryBufferType)
+
+IPC_STRUCT_TRAITS_BEGIN(gfx::GpuMemoryBufferHandle)
+  IPC_STRUCT_TRAITS_MEMBER(type)
+  IPC_STRUCT_TRAITS_MEMBER(handle)
+IPC_STRUCT_TRAITS_END()
+
 #undef IPC_MESSAGE_EXPORT
 #define IPC_MESSAGE_EXPORT CONTENT_EXPORT
 
@@ -138,3 +146,8 @@ IPC_SYNC_MESSAGE_CONTROL1_1(ChildProcessHostMsg_SyncAllocateSharedMemory,
 IPC_MESSAGE_CONTROL1(ChildProcessHostMsg_TcmallocStats,
                      std::string /* output */)
 #endif
+
+// Asks the browser to create a gpu memory buffer.
+IPC_SYNC_MESSAGE_CONTROL1_1(ChildProcessHostMsg_SyncAllocateGpuMemoryBuffer,
+                            uint32 /* buffer size */,
+                            gfx::GpuMemoryBufferHandle)