Add EventForwarder for routing touch events

ui/events/android/motion_event_android.h

Index: ui/events/android/motion_event_android.h
diff --git a/ui/events/android/motion_event_android.h b/ui/events/android/motion_event_android.h
index 00fc4216c58d8240c61369afb3c15058af465232..45fc1988b6214f5893aa7eccca4ba09a8ec7f7bc 100644
--- a/ui/events/android/motion_event_android.h
+++ b/ui/events/android/motion_event_android.h
@@ -54,6 +54,7 @@ class EVENTS_EXPORT MotionEventAndroid : public MotionEvent {
                      jint pointer_count,
                      jint history_size,
                      jint action_index,
+                     jint android_action_button,
                      jint android_button_state,
                      jint meta_state,
                      jfloat raw_offset_x_pixels,
@@ -62,6 +63,8 @@ class EVENTS_EXPORT MotionEventAndroid : public MotionEvent {
                      const Pointer* const pointer1);
   ~MotionEventAndroid() override;
 
+  MotionEventAndroid(const MotionEventAndroid& e, float x, float y);

[boliu, 2017/03/03 22:01:32]

can we just have an offset(x,y) method that returns a new instance?

[Jinsuk Kim, 2017/03/06 04:07:34]

Done this way since copy/Assign is disallowed. See my old reply to aelias@'
command.

[boliu, 2017/03/06 22:08:04]

oh is it because the return by value is a copy? Parent class has
std::unique_ptr<MotionEvent> MotionEvent::Clone. so I guess you can return a
unique_ptr from offset too?


Anyway, this is a really odd subclass.. Calling Clone on this class will return
a MotionEventGeneric right now afaict o_O

[Jinsuk Kim, 2017/03/07 05:02:23]

Added |Offset| that returns std::unique_ptr, and also added the private copy ctr
for that, since it's hard to make use of the existing ctr to create a new
instance from another one (most params are translated to something else at
construction).

+
   // ui::MotionEvent methods.
   uint32_t GetUniqueEventId() const override;
   Action GetAction() const override;
@@ -91,11 +94,17 @@ class EVENTS_EXPORT MotionEventAndroid : public MotionEvent {
   int GetButtonState() const override;
   int GetFlags() const override;
 
+  int GetActionButton() const;
+  base::android::ScopedJavaLocalRef<jobject> GetJavaObject() const;
+
  private:
   struct CachedPointer;
 
   float ToDips(float pixels) const;
   CachedPointer FromAndroidPointer(const Pointer& pointer) const;
+  CachedPointer FromCachedPointer(const CachedPointer& pointer,
+                                  float x,
+                                  float y) const;
 
   // Cache pointer coords, id's and major lengths for the most common
   // touch-related scenarios, i.e., scrolling and pinching.  This prevents
@@ -114,6 +123,7 @@ class EVENTS_EXPORT MotionEventAndroid : public MotionEvent {
   const size_t cached_pointer_count_;
   const size_t cached_history_size_;
   const int cached_action_index_;
+  const int cached_action_button_;
   const int cached_button_state_;
   const int cached_flags_;
   const gfx::Vector2dF cached_raw_position_offset_;