Add optimization for CHROMIUM_subscribe_uniform extension.

content/browser/gpu/gpu_process_host.cc

Index: content/browser/gpu/gpu_process_host.cc
diff --git a/content/browser/gpu/gpu_process_host.cc b/content/browser/gpu/gpu_process_host.cc
index 2d04cb9be80970aaf82e0577ceb30d04a5c628c5..d9adc722e19a32c5b307fb65df29058da25f880e 100644
--- a/content/browser/gpu/gpu_process_host.cc
+++ b/content/browser/gpu/gpu_process_host.cc
@@ -141,6 +141,16 @@ void SendGpuProcessMessage(GpuProcessHost::GpuProcessKind kind,
   }
 }
 
+void SendGpuProcessUpdateValueStateMessage(int client_id,
+                                           unsigned int target,
+                                           const gpu::ValueState& state) {
+  GpuProcessHost* host = GpuProcessHost::Get(
+      GpuProcessHost::GPU_PROCESS_KIND_SANDBOXED,
+      CAUSE_FOR_GPU_LAUNCH_NO_LAUNCH);
+  if (host)
+    host->SendUpdateValueState(client_id, target, state);
+}
+
 // NOTE: changes to this class need to be reviewed by the security team.
 class GpuSandboxedProcessLauncherDelegate
     : public SandboxedProcessLauncherDelegate {
@@ -349,6 +359,15 @@ void GpuProcessHost::SendOnIO(GpuProcessKind kind,
   }
 }
 
+//static
+void GpuProcessHost::SendUpdateValueStateOnIOThread(
+    int client_id, unsigned int target, const gpu::ValueState& state) {
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&SendGpuProcessUpdateValueStateMessage,
+                 client_id, target, state));
+}
+
 GpuMainThreadFactoryFunction g_gpu_main_thread_factory = NULL;
 
 void GpuProcessHost::RegisterGpuMainThreadFactory(
@@ -582,7 +601,8 @@ bool GpuProcessHost::OnMessageReceived(const IPC::Message& message) {
                         OnDestroyChannel)
     IPC_MESSAGE_HANDLER(GpuHostMsg_CacheShader,
                         OnCacheShader)
-
+    IPC_MESSAGE_HANDLER(GpuHostMsg_AddSubscription, OnAddSubscription)
+    IPC_MESSAGE_HANDLER(GpuHostMsg_RemoveSubscription, OnRemoveSubscription)
     IPC_MESSAGE_UNHANDLED(RouteOnUIThread(message))
   IPC_END_MESSAGE_MAP()
 
@@ -1039,6 +1059,15 @@ void GpuProcessHost::LoadedShader(const std::string& key,
     Send(new GpuMsg_LoadedShader(data));
 }
 
+void GpuProcessHost::SendUpdateValueState(int client_id,
+                                          unsigned int target,
+                                          const gpu::ValueState& state) {
+  // Only send data if a valuebuffer is subscribed to the target
+  if (subscription_set_.find(target) != subscription_set_.end()) {
+    Send(new GpuMsg_UpdateValueState(client_id, target, state));
+  }
+}
+
 void GpuProcessHost::CreateChannelCache(int32 client_id) {
   TRACE_EVENT0("gpu", "GpuProcessHost::CreateChannelCache");
 
@@ -1069,4 +1098,12 @@ void GpuProcessHost::OnCacheShader(int32 client_id,
   iter->second->Cache(GetShaderPrefixKey() + ":" + key, shader);
 }
 
+void GpuProcessHost::OnAddSubscription(unsigned int target) {
+  subscription_set_.insert(target);
+}
+
+void GpuProcessHost::OnRemoveSubscription(unsigned int target) {
+  subscription_set_.erase(target);
+}
+
 }  // namespace content