[Android] Select text when stylus first button is pressed.

ui/events/gestures/motion_event_aura.h

Index: ui/events/gestures/motion_event_aura.h
diff --git a/ui/events/gestures/motion_event_aura.h b/ui/events/gestures/motion_event_aura.h
index 7ebf264103ff7403c5bb6187f460ec1fc2e89581..431c0486f791c25a95434db831aa325c15a9e723 100644
--- a/ui/events/gestures/motion_event_aura.h
+++ b/ui/events/gestures/motion_event_aura.h
@@ -48,6 +48,8 @@ class EVENTS_EXPORT MotionEventAura : public MotionEvent {
                                size_t historical_index) const OVERRIDE;
   virtual float GetHistoricalY(size_t pointer_index,
                                size_t historical_index) const OVERRIDE;
+  virtual int GetSource() const OVERRIDE;
+  virtual int GetButtonState() const OVERRIDE;
 
   virtual scoped_ptr<MotionEvent> Clone() const OVERRIDE;
   virtual scoped_ptr<MotionEvent> Cancel() const OVERRIDE;