Implemented new fence syncs which replaces the old sync points.

content/common/gpu/gpu_channel.h

Index: content/common/gpu/gpu_channel.h
diff --git a/content/common/gpu/gpu_channel.h b/content/common/gpu/gpu_channel.h
index d51a98ba2761383b87df9247cfe2f7ffc2adb608..623bc380e8f542251df80c086c30a0fa1d5c8629 100644
--- a/content/common/gpu/gpu_channel.h
+++ b/content/common/gpu/gpu_channel.h
@@ -115,6 +115,10 @@ class CONTENT_EXPORT GpuChannel
   void OnAddSubscription(unsigned int target) override;
   void OnRemoveSubscription(unsigned int target) override;
 
+  // Add callback when a specific order number has been processed.
+  void AddProcessedOrderNumberCallback(uint32_t order_number,
+                                       const base::Closure& callback);
+
   // This is called when a command buffer transitions from the unscheduled
   // state to the scheduled state, which potentially means the channel
   // transitions from the unscheduled to the scheduled state. When this occurs
@@ -210,6 +214,21 @@ class CONTENT_EXPORT GpuChannel
     base::hash_set<int32> routes_;
   };
 
+  struct OrderCallback {
+    uint32_t order_number;
+    base::Closure callback_closure;
+
+    OrderCallback(uint32_t order_num, const base::Closure& callback);
+    ~OrderCallback();
+
+    bool operator>(const OrderCallback& rhs) const {
+      return order_number > rhs.order_number;
+    }
+  };
+  typedef std::priority_queue<OrderCallback,
+                              std::vector<OrderCallback>,
+                              std::greater<OrderCallback>> OrderCallbackQueue;
+
   friend class GpuChannelMessageFilter;
   friend class GpuChannelMessageQueue;
 
@@ -291,6 +310,9 @@ class CONTENT_EXPORT GpuChannel
   // Map of stream id to stream state.
   base::hash_map<int32, StreamState> streams_;
 
+  // Callbacks as each order number is processed.
+  OrderCallbackQueue processed_order_callbacks_;
+
   bool allow_future_sync_points_;
   bool allow_real_time_streams_;