Enable Try Dart to run on IE11.

site/try/src/compilation.dart

Index: site/try/src/compilation.dart
===================================================================
--- site/try/src/compilation.dart	(revision 38416)
+++ site/try/src/compilation.dart	(working copy)
@@ -33,6 +33,8 @@
 
 import 'settings.dart' show
     alwaysRunInWorker,
+    alwaysRunInIframe,
+    communicateViaBlobs,
     incrementalCompilation,
     minified,
     onlyAnalyze,
@@ -110,6 +112,8 @@
     }
     interaction.compilationStarting();
     compilerPort.send([['options', options], receivePort.sendPort]);
+    compilerPort.send([['communicateViaBlobs', communicateViaBlobs],
+                       receivePort.sendPort]);
     receivePort.listen(onMessage);
     compilerPort.send([source, receivePort.sendPort]);
   }
@@ -214,7 +218,8 @@
           ..appendText('\n');
     }
     interaction.aboutToRun();
-    if (usesDartHtml && !alwaysRunInWorker) {
+    if (alwaysRunInIframe ||
+        usesDartHtml && !alwaysRunInWorker) {
       retryInIframe();
     } else {
       runInWorker(url, onError);