Fixing up setting styles to invalidate on IE9.

lib/html/templates/html/impl/impl_CSSStyleDeclaration.darttemplate

Index: lib/html/templates/html/impl/impl_CSSStyleDeclaration.darttemplate
diff --git a/lib/html/templates/html/impl/impl_CSSStyleDeclaration.darttemplate b/lib/html/templates/html/impl/impl_CSSStyleDeclaration.darttemplate
index d928c1d05715c1967132518f4121e1a01da83942..45993d720015745d5f3e2980c1d2270baa4a8249 100644
--- a/lib/html/templates/html/impl/impl_CSSStyleDeclaration.darttemplate
+++ b/lib/html/templates/html/impl/impl_CSSStyleDeclaration.darttemplate
@@ -23,6 +23,16 @@ class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 
 $!MEMBERS
 
+$if DART2JS
+  void setProperty(String propertyName, String value, [String priority]) native '''
+    this.setProperty(propertyName, value, priority);
+    // Bug #2772, IE9 requires a poke to actually apply the value.
+    if (this.setAttribute) {
+      this.setAttribute(propertyName, value);
+    }
+  ''';
+$endif
+
   // TODO(jacobr): generate this list of properties using the existing script.
     /** Gets the value of "animation" */
   String get animation =>