Implemented new fence syncs which replaces the old sync points.

content/common/gpu/gpu_channel.cc

Index: content/common/gpu/gpu_channel.cc
diff --git a/content/common/gpu/gpu_channel.cc b/content/common/gpu/gpu_channel.cc
index c16db443bebd86e23724f6d10408f224840c5524..99b1038fb50a382fe1a70881c08a0a9fd690a6cf 100644
--- a/content/common/gpu/gpu_channel.cc
+++ b/content/common/gpu/gpu_channel.cc
@@ -593,6 +593,12 @@ bool GpuChannel::StreamState::HasRoutes() const {
   return !routes_.empty();
 }
 
+GpuChannel::OrderCallback::OrderCallback(uint32_t order_num,
+                                         const base::Closure& callback)
+    : order_number(order_num), callback_closure(callback) {}
+
+GpuChannel::OrderCallback::~OrderCallback() {}
+
 GpuChannel::GpuChannel(GpuChannelManager* gpu_channel_manager,
                        GpuWatchdog* watchdog,
                        gfx::GLShareGroup* share_group,
@@ -712,6 +718,12 @@ void GpuChannel::OnRemoveSubscription(unsigned int target) {
       new GpuHostMsg_RemoveSubscription(client_id_, target));
 }
 
+void GpuChannel::AddProcessedOrderNumberCallback(
+    uint32_t order_number,
+    const base::Closure& callback) {
+  processed_order_callbacks_.push(OrderCallback(order_number, callback));
+}
+
 void GpuChannel::StubSchedulingChanged(bool scheduled) {
   bool a_stub_was_descheduled = num_stubs_descheduled_ > 0;
   if (scheduled) {
@@ -1083,6 +1095,12 @@ void GpuChannel::MessageProcessed(uint32_t order_number) {
     DCHECK(current_order_num_ == order_number);
     DCHECK(processed_order_num_ < order_number);
     processed_order_num_ = order_number;
+
+    while (!processed_order_callbacks_.empty() &&
+           processed_order_callbacks_.top().order_number <= order_number) {
+      processed_order_callbacks_.top().callback_closure.Run();
+      processed_order_callbacks_.pop();
+    }
   }
   if (preempting_flag_.get()) {
     io_task_runner_->PostTask(