Implemented new fence syncs which replaces the old sync points.

content/common/gpu/client/command_buffer_proxy_impl.h

Index: content/common/gpu/client/command_buffer_proxy_impl.h
diff --git a/content/common/gpu/client/command_buffer_proxy_impl.h b/content/common/gpu/client/command_buffer_proxy_impl.h
index 98f8ed7e2e570907f24d43fed42cd3d754417775..61ba77585f6cf17ba83ba018b4c193533395d00f 100644
--- a/content/common/gpu/client/command_buffer_proxy_impl.h
+++ b/content/common/gpu/client/command_buffer_proxy_impl.h
@@ -123,6 +123,9 @@ class CommandBufferProxyImpl
   bool IsGpuChannelLost() override;
   gpu::CommandBufferNamespace GetNamespaceID() const override;
   uint64_t GetCommandBufferID() const override;
+  uint64_t GenerateFenceSyncRelease() override;
+  bool IsFenceSyncRelease(uint64_t release) override;
+  bool IsFenceSyncFlushed(uint64_t release) override;
 
   bool ProduceFrontBuffer(const gpu::Mailbox& mailbox);
   void SetContextLostCallback(const base::Closure& callback);
@@ -191,6 +194,9 @@ class CommandBufferProxyImpl
   // Try to read an updated copy of the state from shared memory.
   void TryUpdateState();
 
+  // Updates the highest verified release fence sync.
+  void UpdateVerifiedReleases(uint32_t verified_flush);
+
   // The shared memory area used to update state.
   gpu::CommandBufferSharedState* shared_state() const;
 
@@ -215,6 +221,18 @@ class CommandBufferProxyImpl
   int32 last_put_offset_;
   int32 last_barrier_put_offset_;
 
+  // Next generated fence sync.
+  uint64_t next_fence_sync_release_;
+
+  // Unverified flushed fence syncs with their corresponding flush id.
+  std::queue<std::pair<uint64_t, uint32_t>> flushed_release_flush_id_;
+
+  // Last flushed fence sync release, same as last item in queue if not empty.
+  uint64_t flushed_fence_sync_release_;
+
+  // Last verified fence sync.
+  uint64_t verified_fence_sync_release_;
+
   base::Closure context_lost_callback_;
 
   GpuConsoleMessageCallback console_message_callback_;