gpu: Thread-safe command buffer state lookup.

gpu/command_buffer/client/gles2_implementation.cc

 // 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.
 
 // A class to emulate GLES2 over command buffers.
 
 #include "gpu/command_buffer/client/gles2_implementation.h"
 
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
@@ skipping 387 matching lines @@
         intermediate_sync_token,
         base::Bind(&GLES2Implementation::RunIfContextNotLost,
                    weak_ptr_factory_.GetWeakPtr(),
                    callback));
   } else {
     // Invalid sync token, just call the callback immediately.
     callback.Run();
   }
 }
 
+bool GLES2Implementation::IsFenceSyncReleased(uint64_t release_count) {

[piman, 2016/12/02 19:21:48]

nit: please add a comment that this can be called on any thread without locking,
so we can only access (read) constant fields (such as gpu_control_ - we may even
want to indicate that on the field).

[sunnyps, 2016/12/07 03:31:22]

Done.

+  return gpu_control_->IsFenceSyncReleased(release_count);
+}
+
 void GLES2Implementation::SignalQuery(uint32_t query,
                                       const base::Closure& callback) {
   // Flush previously entered commands to ensure ordering with any
   // glBeginQueryEXT() calls that may have been put into the context.
   ShallowFlushCHROMIUM();
   gpu_control_->SignalQuery(
       query,
       base::Bind(&GLES2Implementation::RunIfContextNotLost,
                  weak_ptr_factory_.GetWeakPtr(),
                  callback));
@@ skipping 6612 matching lines @@
   cached_extensions_.clear();
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/client/gles2_implementation_impl_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu