gpu: Refactor memory buffer handling code out of content.

services/ui/public/interfaces/gpu_service.mojom

Index: services/ui/public/interfaces/gpu_service.mojom
diff --git a/services/ui/public/interfaces/gpu_service.mojom b/services/ui/public/interfaces/gpu_service.mojom
index feaeeb7c37971682581c74a1566d31f2b6647b08..b3c0fe726006fcc0fccfda322daa7c75a46447b8 100644
--- a/services/ui/public/interfaces/gpu_service.mojom
+++ b/services/ui/public/interfaces/gpu_service.mojom
@@ -20,11 +20,11 @@ interface GpuService {
                             gpu.mojom.GpuInfo gpu_info);
 
   // Tells the GPU service to create a new GPU memory buffer.
+  [Sync]
   CreateGpuMemoryBuffer(gfx.mojom.GpuMemoryBufferId id,
                         gfx.mojom.Size size,
                         gfx.mojom.BufferFormat format,
-                        gfx.mojom.BufferUsage usage,
-                        uint64 surface_id)
+                        gfx.mojom.BufferUsage usage)
       => (gfx.mojom.GpuMemoryBufferHandle buffer_handle);
 
   // Tells the GPU process to destroy GPU memory buffer.