Reorganize GUIDs for GPU memory buffers

ui/gfx/gpu_memory_buffer.h

Index: ui/gfx/gpu_memory_buffer.h
diff --git a/ui/gfx/gpu_memory_buffer.h b/ui/gfx/gpu_memory_buffer.h
index df0112db5ca1386360080e9121ca80544fe02212..6d23c84ddc76074fc8bd5f13af1460e6b3c70531 100644
--- a/ui/gfx/gpu_memory_buffer.h
+++ b/ui/gfx/gpu_memory_buffer.h
@@ -9,6 +9,7 @@
 #include <stdint.h>
 
 #include "base/memory/shared_memory.h"
+#include "base/trace_event/memory_allocator_dump_guid.h"
 #include "build/build_config.h"
 #include "ui/gfx/buffer_types.h"
 #include "ui/gfx/generic_shared_memory_id.h"
@@ -97,6 +98,10 @@ class GFX_EXPORT GpuMemoryBuffer {
 
   // Type-checking downcast routine.
   virtual ClientBuffer AsClientBuffer() = 0;
+
+  // Returns the GUID for tracing.

[reveman, 2017/04/18 13:44:53]

nit: please add a TODO and a link to a bug as you explained that this is a
temporary solution.

[hajimehoshi, 2017/04/19 06:15:12]

What is temporary is implementation of GetSharedMemoryGUIDForTracing, which will
be replaced with SharedMemoryTracker's. I've already commented in
GetSharedMemoryGUIDForTracing.

+  virtual base::trace_event::MemoryAllocatorDumpGuid GetGUIDForTracing(
+      uint64_t tracing_process_id) const;
 };
 
 // Returns an instance of |handle| which can be sent over IPC. This duplicates