gpu: Simplify the error handling during gpu memory buffer allocation.

content/browser/gpu/gpu_process_host.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_GPU_GPU_PROCESS_HOST_H_
 #define CONTENT_BROWSER_GPU_GPU_PROCESS_HOST_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 61 matching lines @@
                         // while processing the request (e.g. the gpu process
                         // may have been killed). The caller should normally
                         // make another request to establish a new channel.
     SUCCESS
   };
   using EstablishChannelCallback =
       base::Callback<void(const IPC::ChannelHandle&,
                           const gpu::GPUInfo&,
                           EstablishChannelStatus status)>;
 
-  typedef base::Callback<void(const gfx::GpuMemoryBufferHandle& handle)>
-      CreateGpuMemoryBufferCallback;
+  enum class BufferCreationStatus {
+    GPU_HOST_INVALID,
+    SUCCESS,
+  };
+  using CreateGpuMemoryBufferCallback =
+      base::Callback<void(const gfx::GpuMemoryBufferHandle& handle,
+                          BufferCreationStatus status)>;
 
   static bool gpu_enabled() { return gpu_enabled_; }
   static int gpu_crash_count() { return gpu_crash_count_; }
 
   // Creates a new GpuProcessHost (if |force_create| is turned on) or gets an
   // existing one, resulting in the launching of a GPU process if required.
   // Returns null on failure. It is not safe to store the pointer once control
   // has returned to the message loop as it can be destroyed. Instead store the
   // associated GPU host ID.  This could return NULL if GPU access is not
   // allowed (blacklisted).
@@ skipping 201 matching lines @@
   gpu::GpuProcessHostActivityFlags activity_flags_;
 
   base::WeakPtrFactory<GpuProcessHost> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuProcessHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_GPU_GPU_PROCESS_HOST_H_