gpu: Thread-safe command buffer state lookup.

gpu/ipc/client/command_buffer_proxy_impl.h

Index: gpu/ipc/client/command_buffer_proxy_impl.h
diff --git a/gpu/ipc/client/command_buffer_proxy_impl.h b/gpu/ipc/client/command_buffer_proxy_impl.h
index 89300514ca5aec9da9fb5178c788aba04928ad1c..ec9f41c10956c7795442a6f1a4122d617d438d57 100644
--- a/gpu/ipc/client/command_buffer_proxy_impl.h
+++ b/gpu/ipc/client/command_buffer_proxy_impl.h
@@ -99,8 +99,8 @@ class GPU_EXPORT CommandBufferProxyImpl
   int32_t GetLastToken() override;
   void Flush(int32_t put_offset) override;
   void OrderingBarrier(int32_t put_offset) override;
-  void WaitForTokenInRange(int32_t start, int32_t end) override;
-  void WaitForGetOffsetInRange(int32_t start, int32_t end) override;
+  State WaitForTokenInRange(int32_t start, int32_t end) override;
+  State WaitForGetOffsetInRange(int32_t start, int32_t end) override;
   void SetGetBuffer(int32_t shm_id) override;
   scoped_refptr<gpu::Buffer> CreateTransferBuffer(size_t size,
                                                   int32_t* id) override;
@@ -128,6 +128,7 @@ class GPU_EXPORT CommandBufferProxyImpl
   bool IsFenceSyncRelease(uint64_t release) override;
   bool IsFenceSyncFlushed(uint64_t release) override;
   bool IsFenceSyncFlushReceived(uint64_t release) override;
+  bool IsFenceSyncReleased(uint64_t release) override;
   void SignalSyncToken(const gpu::SyncToken& sync_token,
                        const base::Closure& callback) override;
   bool CanWaitUnverifiedSyncToken(const gpu::SyncToken* sync_token) override;
@@ -210,10 +211,13 @@ class GPU_EXPORT CommandBufferProxyImpl
 
   // Try to read an updated copy of the state from shared memory, and calls
   // OnGpuStateError() if the new state has an error.
-  void TryUpdateState();
+  State TryUpdateState();
+  // Like above but calls the error handler and disconnects channel by posting
+  // a task.
+  State TryUpdateStateThreadSafe();
   // Like the above but does not call the error event handler if the new state
   // has an error.
-  void TryUpdateStateDontReportError();
+  State TryUpdateStateDontReportError();
   // Sets the state, and calls OnGpuStateError() if the new state has an error.
   void SetStateFromSyncReply(const gpu::CommandBuffer::State& state);
 
@@ -240,6 +244,10 @@ class GPU_EXPORT CommandBufferProxyImpl
   // The shared memory area used to update state.
   gpu::CommandBufferSharedState* shared_state() const;
 
+  // Lock to access shared state e.g. sync token release count across multiple
+  // threads. This allows tracking command buffer progress from another thread.
+  base::Lock state_lock_;
+
   // There should be a lock_ if this is going to be used across multiple
   // threads, or we guarantee it is used by a single thread by using a thread
   // checker if no lock_ is set.