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

ui/events/gestures/motion_event_aura.cc

Index: ui/events/gestures/motion_event_aura.cc
diff --git a/ui/events/gestures/motion_event_aura.cc b/ui/events/gestures/motion_event_aura.cc
index 2bf4e9b3ce70005b1a0cb67a13f29dbe72d48bb9..7eaf4617195c94fd91770520b67e6169b6e7e01e 100644
--- a/ui/events/gestures/motion_event_aura.cc
+++ b/ui/events/gestures/motion_event_aura.cc
@@ -156,6 +156,16 @@ float MotionEventAura::GetHistoricalY(size_t pointer_index,
   return 0;
 }
 
+int MotionEventAura::GetSource() const {
+  NOTIMPLEMENTED();
+  return 0;
+}
+
+int MotionEventAura::GetButtonState() const {
+  NOTIMPLEMENTED();
+  return 0;
+}
+
 scoped_ptr<MotionEvent> MotionEventAura::Clone() const {
   return scoped_ptr<MotionEvent>(new MotionEventAura(pointer_count_,
                                                      last_touch_time_,