Store the id of a contributing motion event in GestureEventData

content/browser/renderer_host/input/motion_event_android.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/input/motion_event_android.h"
 
 #include "base/android/jni_android.h"
 #include "jni/MotionEvent_jni.h"
 
 using base::android::AttachCurrentThread;
@@ skipping 127 matching lines @@
     cached_pointer_ids_[i] = other.cached_pointer_ids_[i];
     cached_touch_majors_[i] = other.cached_touch_majors_[i];
   }
 }
 
 MotionEventAndroid::~MotionEventAndroid() {
   if (should_recycle_)
     Java_MotionEvent_recycle(AttachCurrentThread(), event_.obj());
 }
 
+int MotionEventAndroid::GetId() const {
+  return 0;
+}
+
 MotionEventAndroid::Action MotionEventAndroid::GetAction() const {
   return cached_action_;
 }
 
 int MotionEventAndroid::GetActionIndex() const {
   return cached_action_index_;
 }
 
 size_t MotionEventAndroid::GetPointerCount() const {
   return cached_pointer_count_;
@@ skipping 120 matching lines @@
   return Java_MotionEvent_obtainAVME_J_J_I_F_F_I(AttachCurrentThread(),
                                                  ToAndroidTime(down_time),
                                                  ToAndroidTime(event_time),
                                                  ToAndroidAction(action),
                                                  x,
                                                  y,
                                                  0);
 }
 
 }  // namespace content