Run VDA::Decode on GPU IO thread if VDA supports it.

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 2b920d3a0704dfeffefb4c62887227867abed977..0cdc5816643bad4cb65b804c5583b1e6c1ad85d8 100644
--- a/content/common/gpu/gpu_channel.cc
+++ b/content/common/gpu/gpu_channel.cc
@@ -104,6 +104,14 @@ class GpuChannelMessageFilter : public IPC::ChannelProxy::MessageFilter {
     channel_ = NULL;
   }
 
+  void AddRoute(int32 route_id, IPC::Listener* listener) {
+    router_.AddRoute(route_id, listener);
+  }
+
+  void RemoveRoute(int32 route_id) {
+    router_.RemoveRoute(route_id);
+  }
+
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE {
     DCHECK(channel_);
 
@@ -122,6 +130,10 @@ class GpuChannelMessageFilter : public IPC::ChannelProxy::MessageFilter {
       handled = true;
     }
 
+    if (message.type() == AcceleratedVideoDecoderMsg_Decode::ID) {
+      handled = router_.RouteMessage(message);
+    }
+
     // All other messages get processed by the GpuChannel.
     if (!handled) {
       messages_forwarded_to_channel_++;
@@ -428,6 +440,9 @@ class GpuChannelMessageFilter : public IPC::ChannelProxy::MessageFilter {
   bool a_stub_is_descheduled_;
 
   crypto::HMAC hmac_;
+
+  // Used to implement message routing functionality running on IO thread.
+  MessageRouter router_;
 };
 
 GpuChannel::GpuChannel(GpuChannelManager* gpu_channel_manager,
@@ -720,6 +735,15 @@ void GpuChannel::RemoveRoute(int32 route_id) {
   router_.RemoveRoute(route_id);
 }
 
+void GpuChannel::AddMessageFilterRoute(int32 route_id,
+                                       IPC::Listener* listener) {
+  filter_->AddRoute(route_id, listener);
+}
+
+void GpuChannel::RemoveMessageFilterRoute(int32 route_id) {
+  filter_->RemoveRoute(route_id);
+}
+
 gpu::PreemptionFlag* GpuChannel::GetPreemptionFlag() {
   if (!preempting_flag_.get()) {
     preempting_flag_ = new gpu::PreemptionFlag;