Make the AnimationController class future compatible, and also change it to

client/base/AnimationScheduler.dart

Index: client/base/AnimationScheduler.dart
===================================================================
--- client/base/AnimationScheduler.dart	(revision 386)
+++ client/base/AnimationScheduler.dart	(working copy)
@@ -43,7 +43,7 @@
   bool _isMobileSafari = false;
   Css _safariHackCss;
   int _frameCount = 0;
-  bool _webkitAnimationFrameMaybeAvailable = true;
+  bool _animationFrameMaybeAvailable = true;
 
   AnimationScheduler()
     : _callbacks = new List<CallbackData>() {
@@ -93,17 +93,35 @@
     if (USE_INTERVALS) {
       _intervalId = window.setInterval(_step, MS_PER_FRAME);
     } else {
-      if (_webkitAnimationFrameMaybeAvailable) {
+      if (_animationFrameMaybeAvailable) {
+        // First try to see if the browser supports the requestAnimationFrame API,
+        // and if that check fails, fall back to using WebKit/Mozilla/IE specific
+        // versions of the API.
         try {
           // TODO(jacobr): passing in document should not be required.
-          _intervalId = window.webkitRequestAnimationFrame(
+          _intervalId = window.requestAnimationFrame(

[Jacob, 2011/10/17 18:24:57]

This approach would cause multiple exceptions to be thrown every time an
animation frame is requested under Mozilla or IE.  To avoid this, we'd need to
track which animation frame callback worked and cache that Function.

               (int ignored) { _step(); }, document);
               // TODO(jacobr) fix this odd type error.
         } catch (var e) {
-          _webkitAnimationFrameMaybeAvailable = false;
+          try {
+            _intervalId = window.webkitRequestAnimationFrame(
+                (int ignored) { _step(); }, document);
+          } catch (var e) {
+            try {

[Jacob, 2011/10/17 18:24:57]

at some point, window.mozRequestAnimationFrame might work with dart:dom 
but at the moment the dart:dom bindings are WebKit specific so
window.mozRequestAnimationFrame will fail even on versions of Mozilla that
support it.

+              _intervalId = window.mozRequestAnimationFrame(
+                  (int ignored) { _step(); }, document);
+            } catch (e) {
+              try {
+                _intervalId = window.msRequestAnimationFrame(
+                    (int ignored) { _step(); }, document);
+              } catch (var e) {
+                _animationFrameMaybeAvailable = false;
+              }
+            }
+          }
         }
       }
-      if (!_webkitAnimationFrameMaybeAvailable) {
+      if (!_animationFrameMaybeAvailable) {
         _intervalId = window.setTimeout(() { _step(); }, MS_PER_FRAME);
       }
     }