Address comments from CL 125123002 and additional cleanup.

dart/site/try/iframe.js

Index: dart/site/try/iframe.js
diff --git a/dart/site/try/iframe.js b/dart/site/try/iframe.js
index 5547e734ca527bdf337ceef5d47cf34ddef66d10..d1460fd6a3e623f4daea91df507a11ddcd4be43f 100644
--- a/dart/site/try/iframe.js
+++ b/dart/site/try/iframe.js
@@ -27,19 +27,25 @@ function onMessageReceived(event) {
 window.addEventListener("message", onMessageReceived, false);
 
 (function () {
-function postScrollHeight() {
-  window.parent.postMessage(["scrollHeight", document.documentElement.scrollHeight], "*");
-}
+  function postScrollHeight() {
+    window.parent.postMessage(
+      ["scrollHeight", document.documentElement.scrollHeight], "*");
+  }
+
+  var mutationObserverConstructor =
+      window.MutationObserver ||
+      window.WebKitMutationObserver ||
+      window.MozMutationObserver;
+
+  var observer = new mutationObserverConstructor(function(mutations) {
+    postScrollHeight()
+    window.setTimeout(postScrollHeight, 500);
+  });
 
-var observer = new (window.MutationObserver||window.WebKitMutationObserver||window.MozMutationObserver)(function(mutations) {
-  postScrollHeight()
-  window.setTimeout(postScrollHeight, 500);
-});
-
-observer.observe(
-    document.body,
-    { attributes: true,
-      childList: true,
-      characterData: true,
-      subtree: true });
+  observer.observe(
+      document.body,
+      { attributes: true,
+        childList: true,
+        characterData: true,
+        subtree: true });
 })();