gpu: log when the request GMB id and the response GMB id are mismatched.

content/browser/gpu/browser_gpu_memory_buffer_manager.cc

 // Copyright 2014 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.
 
 #include "content/browser/gpu/browser_gpu_memory_buffer_manager.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 383 matching lines @@
       gfx::Size size = buffer_it->second.size;
       gfx::BufferFormat format = buffer_it->second.format;
       gfx::BufferUsage usage = buffer_it->second.usage;
       // Remove the buffer entry and call CreateGpuMemoryBufferOnIO again.
       buffers.erase(buffer_it);
       CreateGpuMemoryBufferOnIO(id, size, format, usage, surface_handle,
                                 client_id, callback);
     } else {
       // Remove the buffer entry and run the allocation callback with an empty
       // handle to indicate failure.
+      LOG(ERROR) << "GpuMemoryBuffer ID is mismatched. request id:" << id.id

[reveman, 2017/05/30 18:11:52]

We don't know if it's because a id mismatch here. Could be an allocation failure
and this message is then confusing.

[dshwang, 2017/05/30 18:52:57]

It happens when handle.id != id. please check above if statement.
In addition, if mismatch happens in real, I think it's because gpu process
reorders the request somehow.

+                 << ", response id:" << handle.id.id;
       buffers.erase(buffer_it);
       callback.Run(gfx::GpuMemoryBufferHandle());
     }
     return;
   }
 
   // Store the type and host id of this buffer so it can be cleaned up if the
   // client is removed.
   buffer_it->second.type = handle.type;
   buffer_it->second.gpu_host_id = gpu_host_id;
@@ skipping 56 matching lines @@
       format(format),
       usage(usage),
       gpu_host_id(gpu_host_id) {}
 
 BrowserGpuMemoryBufferManager::BufferInfo::BufferInfo(const BufferInfo& other) =
     default;
 
 BrowserGpuMemoryBufferManager::BufferInfo::~BufferInfo() {}
 
 }  // namespace content