Add setBounds method and browsertest for get/set bounds to app window API

chrome/test/data/extensions/platform_apps/windows_api_bounds/background.js

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+chrome.app.runtime.onLaunched.addListener(function() {
+  chrome.app.window.create("main.html", function(win){
+    // Make sure we get back a bounds and that it isn't all 0's.
+    var bounds = win.getBounds();
+    if (!bounds ||
+        (bounds.top == 0 && bounds.left == 0 &&
+         bounds.width == 0 && bounds.height == 0)) {
+      console.error("invalid bounds after app.window.create:" +
+                    JSON.stringify(bounds));
+      win.close();
+      window.close();
+    } else {
+      chrome.test.sendMessage("background_ok");
+    }
+  });
+});