Add optimization for CHROMIUM_subscribe_uniform extension.

content/common/gpu/gpu_channel_manager.cc

Index: content/common/gpu/gpu_channel_manager.cc
diff --git a/content/common/gpu/gpu_channel_manager.cc b/content/common/gpu/gpu_channel_manager.cc
index 9e5fee4ca191d5963cee8ed82fa329a9db79f205..1a365ca100b81f390eca6012af78db418bb43791 100644
--- a/content/common/gpu/gpu_channel_manager.cc
+++ b/content/common/gpu/gpu_channel_manager.cc
@@ -114,10 +114,13 @@ GpuChannelManager::GpuChannelManager(MessageRouter* router,
   DCHECK(io_message_loop);
   DCHECK(shutdown_event);
   channel_->AddFilter(filter_.get());
+  subscription_ref_set_ = new gpu::gles2::SubscriptionRefSet();
+  subscription_ref_set_->AddObserver(this);
 }
 
 GpuChannelManager::~GpuChannelManager() {
   gpu_channels_.clear();
+  subscription_ref_set_->RemoveObserver(this);
   if (default_offscreen_surface_.get()) {
     default_offscreen_surface_->Destroy();
     default_offscreen_surface_ = NULL;
@@ -186,6 +189,14 @@ bool GpuChannelManager::OnMessageReceived(const IPC::Message& msg) {
 
 bool GpuChannelManager::Send(IPC::Message* msg) { return router_->Send(msg); }
 
+void GpuChannelManager::OnAddSubscription(unsigned int target) {
+  Send(new GpuHostMsg_AddSubscription(target));
+}
+
+void GpuChannelManager::OnRemoveSubscription(unsigned int target) {
+  Send(new GpuHostMsg_RemoveSubscription(target));
+}
+
 void GpuChannelManager::OnEstablishChannel(int client_id,
                                            bool share_context,
                                            bool allow_future_sync_points) {
@@ -207,6 +218,7 @@ void GpuChannelManager::OnEstablishChannel(int client_id,
                                                 watchdog_,
                                                 share_group,
                                                 mailbox_manager,
+                                                subscription_ref_set_.get(),
                                                 client_id,
                                                 false,
                                                 allow_future_sync_points));