Improve drawer performance

sky/services/engine/input_event.mojom

 // Copyright 2015 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.
 
 module sky;
 
 enum EventType {
   UNKNOWN,
   POINTER_CANCEL,
   POINTER_DOWN,
@@ skipping 38 matching lines @@
 struct GestureData {
   int32 primary_pointer;
   float x;
   float y;
   float dx;
   float dy;
   float velocityX;
   float velocityY;
 };
 
+// TODO(abarth): Should we have a malloc-free way of creating an input event
+// message? What we have now could stress out the Android Java GC.
 struct InputEvent {
   EventType type;
   int64 time_stamp;
   PointerData? pointer_data;
   GestureData? gesture_data;
 };