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

content/browser/gpu/browser_gpu_memory_buffer_manager.cc

Index: content/browser/gpu/browser_gpu_memory_buffer_manager.cc
diff --git a/content/browser/gpu/browser_gpu_memory_buffer_manager.cc b/content/browser/gpu/browser_gpu_memory_buffer_manager.cc
index aab62d820de3bac55fa60803a9cc6246165e1294..6571db1f4308e698cc9321e56dbbe3c13ba4bc45 100644
--- a/content/browser/gpu/browser_gpu_memory_buffer_manager.cc
+++ b/content/browser/gpu/browser_gpu_memory_buffer_manager.cc
@@ -401,6 +401,8 @@ void BrowserGpuMemoryBufferManager::GpuMemoryBufferCreatedOnIO(
     } 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());
     }