Set the unique_event_id when converting from TouchEvent to WebTouchEvent

content/browser/renderer_host/input/motion_event_android.h

Index: content/browser/renderer_host/input/motion_event_android.h
diff --git a/content/browser/renderer_host/input/motion_event_android.h b/content/browser/renderer_host/input/motion_event_android.h
index f4e8c9422ddd7778292257818911c2661c033aac..bf4dfed040ecc3be707a4273d0f88b1f056df430 100644
--- a/content/browser/renderer_host/input/motion_event_android.h
+++ b/content/browser/renderer_host/input/motion_event_android.h
@@ -58,7 +58,7 @@ class CONTENT_EXPORT MotionEventAndroid : public ui::MotionEvent {
   ~MotionEventAndroid() override;
 
   // ui::MotionEvent methods.
-  int GetId() const override;
+  uint32 GetUniqueEventId() const override;
   Action GetAction() const override;
   int GetActionIndex() const override;
   size_t GetPointerCount() const override;
@@ -123,6 +123,9 @@ class CONTENT_EXPORT MotionEventAndroid : public ui::MotionEvent {
     ToolType tool_type;
   } cached_pointers_[MAX_POINTERS_TO_CACHE];
 
+  // A unique identifier for the Android motion event.
+  const uint32 unique_event_id_;
+
   DISALLOW_COPY_AND_ASSIGN(MotionEventAndroid);
 };