Add mouse input forwarding to gpu service

content/browser/renderer_host/input/input_router_impl.cc

Index: content/browser/renderer_host/input/input_router_impl.cc
diff --git a/content/browser/renderer_host/input/input_router_impl.cc b/content/browser/renderer_host/input/input_router_impl.cc
index 441f9384bb8745e05efd53d9e1e645aa94255124..451d87bb5d10878741af41ab7cdb23ff841ae13b 100644
--- a/content/browser/renderer_host/input/input_router_impl.cc
+++ b/content/browser/renderer_host/input/input_router_impl.cc
@@ -10,6 +10,7 @@
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_number_conversions.h"
+#include "content/browser/gpu/gpu_process_host.h"
 #include "content/browser/renderer_host/input/gesture_event_queue.h"
 #include "content/browser/renderer_host/input/input_ack_handler.h"
 #include "content/browser/renderer_host/input/input_router_client.h"
@@ -17,6 +18,7 @@
 #include "content/browser/renderer_host/input/touchpad_tap_suppression_controller.h"
 #include "content/common/content_constants_internal.h"
 #include "content/common/edit_command.h"
+#include "content/common/gpu/gpu_messages.h"
 #include "content/common/input/input_event_ack_state.h"
 #include "content/common/input/touch_action.h"
 #include "content/common/input/web_touch_event_traits.h"
@@ -347,6 +349,7 @@ void InputRouterImpl::OfferToHandlers(const WebInputEvent& input_event,
   if (OfferToClient(input_event, latency_info))
     return;
 
+  OfferToGpuService(input_event, is_keyboard_shortcut);
   OfferToRenderer(input_event, latency_info, is_keyboard_shortcut);
 
   // Touch events should always indicate in the event whether they are
@@ -409,6 +412,18 @@ bool InputRouterImpl::OfferToRenderer(const WebInputEvent& input_event,
   return false;
 }
 
+void InputRouterImpl::OfferToGpuService(const blink::WebInputEvent& input_event,
+                                        bool is_keyboard_shortcut) {
+  GpuProcessHost::SendOnIO(
+#if defined(OS_WIN)
+      GpuProcessHost::GPU_PROCESS_KIND_UNSANDBOXED,

[jdduke (slow), 2014/10/13 17:14:45]

Is the GPU service interested in all event types? Even keyboard events? 

Also, even behind a flag, I'm not sure we'd ever want to always blast events
like this unless we had an explicit "subscription" signal from the render
process (pointer lock?). Perhaps someday we can use a similar fast path for
scrolling the page directly in the GPU process...

[orglofch, 2014/10/13 17:30:26]

Only mouse events right now. I can't think of a use case for keyboard events but
I figured that one may arise. I'll filter these for now.
I'll also look into adding a subscription signal 

+#else
+      GpuProcessHost::GPU_PROCESS_KIND_SANDBOXED,
+#endif
+      CAUSE_FOR_GPU_LAUNCH_NO_LAUNCH,
+      new GpuMsg_HandleInputEvent(&input_event, is_keyboard_shortcut));
+}
+
 void InputRouterImpl::SendSyntheticWheelEventForPinch(
     const GestureEventWithLatencyInfo& pinch_event) {
   // We match typical trackpad behavior on Windows by sending fake wheel events