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..0fcd5058da0ce2e248f88539778d9949e8626243 100644
--- a/gpu/command_buffer/client/gles2_implementation.cc
+++ b/gpu/command_buffer/client/gles2_implementation.cc
@@ -405,6 +405,10 @@ void GLES2Implementation::SignalSyncToken(const gpu::SyncToken& sync_token,
   }
 }
 
+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