Revert of Remove smiluate-touch-screen-with-mouse content flag.

content/browser/renderer_host/input/input_router_impl.h

Index: content/browser/renderer_host/input/input_router_impl.h
diff --git a/content/browser/renderer_host/input/input_router_impl.h b/content/browser/renderer_host/input/input_router_impl.h
index 8c512348a6bcf93988e02c4bf627d8055f9ce7fe..6630c9197ca3356439bae6e5c3ff4ae0e761f794 100644
--- a/content/browser/renderer_host/input/input_router_impl.h
+++ b/content/browser/renderer_host/input/input_router_impl.h
@@ -171,6 +171,9 @@
   void ProcessAckForOverscroll(const blink::WebInputEvent& event,
                                InputEventAckState ack_result);
 
+  void SimulateTouchGestureWithMouse(
+      const MouseEventWithLatencyInfo& mouse_event);
+
   // Called when a touch timeout-affecting bit has changed, in turn toggling the
   // touch ack timeout feature of the |touch_event_queue_| as appropriate. Input
   // to that determination includes current view properties, the allowed touch