events: Change gesture-event handler in EventHandler to not return any values.

ash/wm/activation_controller.cc

Index: ash/wm/activation_controller.cc
diff --git a/ash/wm/activation_controller.cc b/ash/wm/activation_controller.cc
index 0810d51b8de38d3ba03833e1699e0557c2832009..337979b98044c34642ba2c386a0b1e62c125f791 100644
--- a/ash/wm/activation_controller.cc
+++ b/ash/wm/activation_controller.cc
@@ -286,12 +286,11 @@ ui::EventResult ActivationController::OnTouchEvent(ui::TouchEvent* event) {
   return ui::ER_UNHANDLED;
 }
 
-ui::EventResult ActivationController::OnGestureEvent(ui::GestureEvent* event) {
+void ActivationController::OnGestureEvent(ui::GestureEvent* event) {
   if (event->type() == ui::ET_GESTURE_BEGIN &&
       event->details().touch_points() == 1) {
     FocusWindowWithEvent(event);
   }
-  return ui::ER_UNHANDLED;
 }
 
 ////////////////////////////////////////////////////////////////////////////////