Add mouse input forwarding to gpu service

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 344032a75a8f43b2137907f525dbea883cdd3a7c..557454a4b22d8f8779388d44bca8aeb4c2ab558a 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -60,6 +60,8 @@
 #include "content/public/common/content_switches.h"
 #include "content/public/common/result_codes.h"
 #include "content/public/common/web_preferences.h"
+#include "gpu/GLES2/gl2extchromium.h"
+#include "gpu/command_buffer/service/gpu_switches.h"
 #include "skia/ext/image_operations.h"
 #include "skia/ext/platform_canvas.h"
 #include "third_party/WebKit/public/web/WebCompositionUnderline.h"
@@ -186,6 +188,7 @@ RenderWidgetHostImpl::RenderWidgetHostImpl(RenderWidgetHostDelegate* delegate,
       allow_privileged_mouse_lock_(false),
       has_touch_handler_(false),
       last_input_number_(static_cast<int64>(GetProcess()->GetID()) << 32),
+      subscribe_uniform_enabled_(false),
       next_browser_snapshot_id_(1),
       browser_composite_latency_history_(kBrowserCompositeLatencyHistorySize),
       weak_factory_(this) {
@@ -234,6 +237,10 @@ RenderWidgetHostImpl::RenderWidgetHostImpl(RenderWidgetHostDelegate* delegate,
         base::Bind(&RenderWidgetHostImpl::RendererIsUnresponsive,
                    weak_factory_.GetWeakPtr())));
   }
+
+  subscribe_uniform_enabled_ =
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableSubscribeUniformExtension);
 }
 
 RenderWidgetHostImpl::~RenderWidgetHostImpl() {
@@ -899,6 +906,19 @@ void RenderWidgetHostImpl::ForwardMouseEventWithLatencyInfo(
 
   input_router_->SendMouseEvent(MouseEventWithLatencyInfo(mouse_event,
                                                           latency_info));
+
+  // Pass mouse state to gpu service if the subscribe uniform
+  // extension is enabled.
+  if (subscribe_uniform_enabled_) {

[piman, 2014/11/21 23:46:38]

It can be done as a follow-up, but I'd like to see this being only enabled once
a context actually subscribes to the value. It will have a non-negligible cost
on all platforms, and we don't want to pay for it when no-one is looking at the
data.

The gpu process can send a message to request the data to be sent (and,
respectively, to stop having it be sent) once the first context subscribes (and
respectively, once the last context stops subscribing).

[orglofch, 2014/11/25 20:05:09]

Acknowledged. Marked as a TODO.

+    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));
+  }
 }
 
 void RenderWidgetHostImpl::OnPointerEventActivate() {