Add optimization for CHROMIUM_subscribe_uniform extension.

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index bfbb78498496f2d9c75c9772ad4079b98d983787..86b95c51e8ae957d341ca053b5be3c382885de47 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -233,6 +233,8 @@ RenderWidgetHostImpl::RenderWidgetHostImpl(RenderWidgetHostDelegate* delegate,
                    weak_factory_.GetWeakPtr())));
   }
 
+  pending_valuebuffer_state_ = new gpu::ValueStateMap();
+
   subscribe_uniform_enabled_ =
       base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableSubscribeUniformExtension);
@@ -904,17 +906,11 @@ void RenderWidgetHostImpl::ForwardMouseEventWithLatencyInfo(
 
   // Pass mouse state to gpu service if the subscribe uniform
   // extension is enabled.
-  // TODO(orglofch): Only pass mouse information if one of the GL Contexts
-  // is subscribed to GL_MOUSE_POSITION_CHROMIUM
   if (subscribe_uniform_enabled_) {
     gpu::ValueState state;
     state.int_value[0] = mouse_event.x;
     state.int_value[1] = mouse_event.y;
-    GpuProcessHost::SendOnIO(
-        GpuProcessHost::GPU_PROCESS_KIND_SANDBOXED,
-        CAUSE_FOR_GPU_LAUNCH_NO_LAUNCH,
-        new GpuMsg_UpdateValueState(
-            process_->GetID(), GL_MOUSE_POSITION_CHROMIUM, state));
+    SendUpdateValueState(GL_MOUSE_POSITION_CHROMIUM, state);
   }
 }
 
@@ -2355,6 +2351,21 @@ void RenderWidgetHostImpl::OnSnapshotDataReceivedAsync(
     OnSnapshotDataReceived(snapshot_id, NULL, 0);
 }
 
+void RenderWidgetHostImpl::SendUpdateValueState(unsigned int target,
+                                                const gpu::ValueState& state) {
+  if (subscription_set_.find(GL_MOUSE_POSITION_CHROMIUM)

[piman, 2014/12/10 06:57:10]

s/GL_MOUSE_POSITION_CHROMIUM/target/ in this method?

[orglofch, 2014/12/10 21:54:48]

Done.

+      != subscription_set_.end()) {
+    GpuProcessHost::SendOnIO(
+        GpuProcessHost::GPU_PROCESS_KIND_SANDBOXED,
+        CAUSE_FOR_GPU_LAUNCH_NO_LAUNCH,
+        new GpuMsg_UpdateValueState(
+            process_->GetID(), GL_MOUSE_POSITION_CHROMIUM, state));

[piman, 2014/12/10 06:57:10]

Actually, I'm realizing, this doesn't make much sense to have a per-process map
that has per-RWH values.

The event is relative to the renderer. You can have different renderers in
different windows, and moving the mouse between those renderers would send
spurious values to the other ones.

That's kind of why you have a strange map lookup in GpuProcessHostUIShim.

[orglofch, 2014/12/10 21:54:48]

Done. Moved to RenderProcessHost.

+  } else {
+    // Store the ValueState locally in case a Valuebuffer subscribes to it later
+    pending_valuebuffer_state_->UpdateState(GL_MOUSE_POSITION_CHROMIUM, state);
+  }
+}
+
 // static
 void RenderWidgetHostImpl::CompositorFrameDrawn(
     const std::vector<ui::LatencyInfo>& latency_info) {
@@ -2411,6 +2422,18 @@ void RenderWidgetHostImpl::AddLatencyInfoComponentIds(
   }
 }
 
+void RenderWidgetHostImpl::OnAddSubscription(unsigned int target) {
+  subscription_set_.insert(target);
+  const gpu::ValueState* state = pending_valuebuffer_state_->GetState(target);
+  if (state) {
+    SendUpdateValueState(target, *state);
+  }
+}
+
+void RenderWidgetHostImpl::OnRemoveSubscription(unsigned int target) {
+  subscription_set_.erase(target);
+}
+
 BrowserAccessibilityManager*
     RenderWidgetHostImpl::GetRootBrowserAccessibilityManager() {
   return delegate_ ? delegate_->GetRootBrowserAccessibilityManager() : NULL;