gpu: Thread-safe command buffer state lookup.

gpu/command_buffer/client/gles2_implementation.cc

Index: gpu/command_buffer/client/gles2_implementation.cc
diff --git a/gpu/command_buffer/client/gles2_implementation.cc b/gpu/command_buffer/client/gles2_implementation.cc
index 3424bc2a5310224463bbed535e1e84eed8e336d0..c7d22194b684e676db2760ef7ed4d05f53148afd 100644
--- a/gpu/command_buffer/client/gles2_implementation.cc
+++ b/gpu/command_buffer/client/gles2_implementation.cc
@@ -405,6 +405,12 @@ void GLES2Implementation::SignalSyncToken(const gpu::SyncToken& sync_token,
   }
 }
 
+// For some command buffer implementations this can be called from any thread.
+// It's safe to access gpu_control_ without the lock because it is const.
+bool GLES2Implementation::IsFenceSyncReleased(uint64_t release_count) {
+  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