gpu: Thread-safe command buffer state lookup.

cc/test/test_context_support.h

Index: cc/test/test_context_support.h
diff --git a/cc/test/test_context_support.h b/cc/test/test_context_support.h
index cbab29656f5a7d7106fa58dedb010fd86552a970..2f1cc997910224cc7f717c39475748310fc9d544 100644
--- a/cc/test/test_context_support.h
+++ b/cc/test/test_context_support.h
@@ -29,6 +29,7 @@ class TestContextSupport : public gpu::ContextSupport {
   // gpu::ContextSupport implementation.
   void SignalSyncToken(const gpu::SyncToken& sync_token,
                        const base::Closure& callback) override;
+  bool IsFenceSyncReleased(uint64_t release) override;
   void SignalQuery(uint32_t query, const base::Closure& callback) override;
   void SetAggressivelyFreeResources(bool aggressively_free_resources) override;
   void Swap() override;