Add method to set action button on MotionEvent

Change-Id: I09f00fa1c2b793a88772f67fe195860ec436179d
diff --git a/include/input/Input.h b/include/input/Input.h
index 1da8356..4a67f47 100644
--- a/include/input/Input.h
+++ b/include/input/Input.h
@@ -383,6 +383,8 @@
 
     inline int32_t getActionButton() const { return mActionButton; }
 
+    inline void setActionButton(int32_t button) { mActionButton = button; }
+
     inline float getXOffset() const { return mXOffset; }
 
     inline float getYOffset() const { return mYOffset; }