Add a webstore API for installing bundles of extensions.

chrome/test/data/extensions/api_test/webstore_private/silently_install.html

+<!--
+ * 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.
+-->
 <script src="common.js"></script>
 <script>
 
 var extension1 = {
   'id': 'bmfoocgfinpmkmlbjhcbofejhkhlbchk',
-  'manifest':
-    '{\
-      "name": "Extension Bundle 1",\
-      "version": "1",\
-      "manifest_version": 2,\
-      "permissions": [ "tabs" ]\
-     }'
+  'manifest': getManifest('bundle/extension1.json')
 };
 
 var extension2 = {
   'id': 'mpneghmdnmaolkljkipbhaienajcflfe',
-  'manifest':
-    '{\
-      "name": "Extension Bundle 2",\
-      "version": "1",\
-      "manifest_version": 2,\
-      "permissions": ["management", "http://google.com" ],\
-      "content_script": [{\
-        "matches": [ "http://www.example.com/*" ],\
-        "js": [ "content_script.js" ],\
-        "run_at": "document_start"\
-       }]\
-    }'
+  'manifest': getManifest('bundle/extension2.json')
 };
 
 var extension3 = {
   'id': 'begfmnajjkbjdgmffnjaojchoncnmngg',
-  'manifest':
-    '{\
-      "name": "Bundle App 2",\
-      "version": "1",\
-      "manifest_version": 2,\
-      "app": {\
-        "urls": [ "http://www.testapp2.com" ],\
-        "launch": { "web_url": "http://www.testapp2.com" }\
-      }\
-    }'
+  'manifest': getManifest('bundle/app2.json')
 };
 
 runTests([
   function invalidID() {
     var expectedError = "Invalid id";
     chrome.webstorePrivate.silentlyInstall(
         { 'id': 'dladmdjkfniedhfhcfoefgojhgaiaccc', 'manifest': getManifest() },
         callbackFail(expectedError));
   },
 
@@ skipping 12 matching lines @@
           extension3, callbackPass(function() {
         checkItemInstalled(
              extension3.id,
              callbackPass(function(result) { assertTrue(result); }));
       }));
     }));
   }
 ]);
 
 </script>