Fixing CssStyleDeclaration to not throw exceptions for unsupported values.

tools/dom/templates/html/impl/impl_CSSStyleDeclaration.darttemplate

Index: tools/dom/templates/html/impl/impl_CSSStyleDeclaration.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_CSSStyleDeclaration.darttemplate b/tools/dom/templates/html/impl/impl_CSSStyleDeclaration.darttemplate
index 6c732494100a92b36c4a390737b2b962badcc236..040a646c8c9bfdd43e44bcf972af8978363c6858 100644
--- a/tools/dom/templates/html/impl/impl_CSSStyleDeclaration.darttemplate
+++ b/tools/dom/templates/html/impl/impl_CSSStyleDeclaration.darttemplate
@@ -53,11 +53,14 @@ $!MEMBERS
 
 $if DART2JS
   void setProperty(String propertyName, String value, [String priority]) {
-    JS('void', '#.setProperty(#, #, #)', this, propertyName, value, priority);
-    // Bug #2772, IE9 requires a poke to actually apply the value.
-    if (JS('bool', '!!#.setAttribute', this)) {
-      JS('void', '#.setAttribute(#, #)', this, propertyName, value);
-    }
+    // try/catch for IE9 which throws on unsupported values.
+    try {
+      JS('void', '#.setProperty(#, #, #)', this, propertyName, value, priority);
+      // Bug #2772, IE9 requires a poke to actually apply the value.
+      if (JS('bool', '!!#.setAttribute', this)) {
+        JS('void', '#.setAttribute(#, #)', this, propertyName, value);
+      }
+    } catch (e) {}
   }
 
   /**