extensions: Register 'app' and 'webstore' bindings only if they are available.

chrome/common/extensions/api/_api_features.json

 // 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.
 
 // This features file defines extension APIs implemented under src/chrome.
 // See extensions/common/features/* to understand this file, in particular
 // feature.h, simple_feature.h, and base_feature_provider.h.
 //
 // Note that specifying "web_page", "blessed_web_page", or "all" as a context
 // type will require manually updating chrome/renderer/resources/dispatcher.cc.
@@ skipping 35 matching lines @@
     ],
     "channel": "stable",
     "extension_types": ["hosted_app", "extension", "legacy_packaged_app"],
     "contexts": [
       "blessed_extension",
       "unblessed_extension",
       "content_script",
       "web_page",
       "blessed_web_page"
     ],
-    "matches": [
-      "http://*/*", "https://*/*", "chrome-extension://*/*", "file://*/*"
-    ]
+    // Any webpage can use the app API.
+    "matches": ["<all_urls>"]
   },
   "appViewInternal": {
     "internal": true,
     "channel": "dev",
     "contexts": ["blessed_extension"]
   },
   "app.window": {
     "channel": "stable",
     "contexts": ["blessed_extension"],
     "extension_types": ["platform_app"],
@@ skipping 687 matching lines @@
     "dependencies": ["permission:webrtcAudioPrivate"],
     "contexts": ["blessed_extension"]
   },
   "webrtcLoggingPrivate": {
     "dependencies": ["permission:webrtcLoggingPrivate"],
     "contexts": ["blessed_extension"]
   },
   "webstore": {
     // Hosted apps can use the webstore API from within a blessed context.
     "channel": "stable",
-    // Do not specify extension_types to prevent webstore from being filtered.
+    // Set extension_types to 'all' to prevent webstore from being filtered.
     // Technically, webstore is not in apps or extensions, but it is currently
     // displayed on /extensions/webstore and /apps/webstore.

[not at google - send to devlin, 2014/08/06 00:21:22]

Also mention: the "contexts" restriction effectively restricts this to hosted
apps and webpages.

[sadrul, 2014/08/06 02:00:13]

Done.

+    "extension_types": "all",
     "contexts": ["blessed_web_page", "web_page"],
     // Any webpage can use the webstore API.
-    "matches": ["http://*/*", "https://*/*"]
+    "matches": ["<all_urls>"]
   },
   "webstorePrivate": {
     "dependencies": ["permission:webstorePrivate"],
     "contexts": ["blessed_extension"]
   },
   "webViewInternal": [{
     "internal": true,
     "dependencies": ["permission:webview"],
     "contexts": ["blessed_extension"]
   }, {
@@ skipping 16 matching lines @@
     "internal": true,
     "channel": "stable",
     "dependencies": ["permission:webview"],
     "contexts": ["blessed_extension"]
   },
   "windows": {
     "dependencies": ["api:tabs"],
     "contexts": ["blessed_extension"]
   }
 }