Avoid crash if setTimeout/clearTimeout is referenced

In some cases, React (or other libraries) will assume that setTimeout
and clearTimeout are defined on the global scope, without invoking it.

We should still throw an error in case a consumer expects this to just
work on the server (it won't), but we can avoid a crash by defining the
function on the global scope.

For context: #555

Author: dustinsoftware

src/React.Core/Resources/shims.js

@@ -3,12 +3,12 @@
  *  All rights reserved.
  *
  *  This source code is licensed under the BSD-style license found in the
- *  LICENSE file in the root directory of this source tree. An additional grant 
+ *  LICENSE file in the root directory of this source tree. An additional grant
  *  of patent rights can be found in the PATENTS file in the same directory.
  */
 
 var global = global || {};
-var React, ReactDOM, ReactDOMServer;
+var React, ReactDOM, ReactDOMServer, setTimeout, clearTimeout;
 
 // Basic console shim. Caches all calls to console methods.
 function MockConsole() {
@@ -68,6 +68,20 @@ function ReactNET_initReact() {
 	return false;
 }
 
+setTimeout = setTimeout || global.setTimeout;
+if (setTimeout === undefined) {
+	setTimeout = function() {
+		throw new Error('setTimeout is not supported in server-rendered Javascript.');
+	}
+}
+
+clearTimeout = clearTimeout || global.clearTimeout;
+if (clearTimeout === undefined) {
+	clearTimeout = function() {
+		throw new Error('clearTimeout is not supported in server-rendered Javascript.');
+	}
+}
+
 /**
  * Polyfill for engines that do not support Object.assign
  */
@@ -94,4 +108,4 @@ if (typeof Object.assign !== 'function') {
 		}
 		return to;
 	};
-}
+}