Backport some work from sample to embedder:

samples/android_sample/assets/dart/main.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import "dart:math" as Math;
 import "android_extension.dart";
 
 const FRAGMENT_PROGRAM = """
   precision mediump float;
 
@@ skipping 301 matching lines @@
   gl.uniform3f(sphere3Center, x3, y3, z3);
 
   gl.drawArrays(WebGLRenderingContext.TRIANGLE_STRIP, 0, 4);
 
   t += 0.03;
   if (t > Math.PI * 200) {
     t -= Math.PI * 200;
   }
 }
 
-setup(int w, int h) {
+setup(int x, int y, int w, int h) {
   initShaders();
   gl.clearColor(0.0, 0.0, 0.0, 1.0);
   gl.clearDepth(1.0);
   initBuffers();
   resize(w, h);
   playBackground("music/la_ere_gymnopedie.mp3");
 }
 
 resize(int w, int h) {
   width = w;
@@ skipping 17 matching lines @@
 onMotionMove(num when, num x, num y) {}
 onMotionCancel(num when, num x, num y) {}
 onMotionOutside(num when, num x, num y) {}
 onMotionPointerDown(num when, num x, num y) {}
 onMotionPointerUp(num when, num x, num y) {}
 onKeyDown(num when, int flags, int keycode, int metastate, int repeat) {}
 onKeyUp(num when, int flags, int keycode, int metastate, int repeat) {}
 onKeyMultiple(num when, int flags, int keycode, int metastate, int repeat) {
 }