maintain Platform alias for bc.

src/WebComponents/bc.js

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
+ * This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+ * The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+ * The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
+ * Code distributed by Google as part of the polymer project is also
+ * subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
+ */
+
+(function(scope) {
+
+  // alias to Platform for bc
+  window.Platform = scope;
+
+})(window.WebComponents);

src/WebComponents/build.json

@@ -9,5 +9,6 @@
   "../CustomElements/build.json",
   "lang.js",
   "dom.js",
-  "unresolved.js"
+  "unresolved.js",
+  "bc.js"
 ]

webcomponents.js

@@ -73,7 +73,9 @@
       'WebComponents/lang.js',
       // these scripts are loaded here due to polyfill timing issues
       'WebComponents/dom.js',
-      'WebComponents/unresolved.js'
+      'WebComponents/unresolved.js',
+      // back compat.
+      'WebComponents/bc.js'
     ]
   );