Adds syncedNotificationsPrivate API IDL.

chrome/common/extensions/api/_permission_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.
 
 // See c/c/e/features/* to understand this file, in particular feature.h,
 // simple_feature.h, and base_feature_provider.h.
 
 // To add a new whitelisted ID, SHA-1 it and force it to uppercase. In Bash:
 //
 // $ echo -n "aaaabbbbccccddddeeeeffffgggghhhh" | \
@@ skipping 805 matching lines @@
       // The connectivity diagnostic utility is a component extension that is
       // used to try to provide suggestions on how to fix connection issues.  It
       // should be the only non-app allowed to use the socket API.
       "32A1BA997F8AB8DE29ED1BA94AAF00CF2A3FEFA7"
     ]
   }],
   "syncFileSystem": {
     "channel": "stable",
     "extension_types": ["platform_app"]
   },
+  "syncedNotificationsPrivate": {
+    "channel": "dev",

[not at google - send to devlin, 2014/05/02 21:37:38]

restrict unimplemented APIs to trunk not dev

[dewittj, 2014/05/03 00:07:49]

Done.

+    "extension_types": ["platform_app"]

[not at google - send to devlin, 2014/05/02 21:37:38]

you will need a whitelist for this eventually? could you artificially restrict
it to component extensions for now, then write your tests against that?

[dewittj, 2014/05/03 00:07:49]

I would rather not have a whitelist so we can hack on it more freely but if you
think that's necessary I could create a web store id etc.  Is it ok to be open
on trunk temporarily?

[not at google - send to devlin, 2014/05/03 00:13:59]

Open on trunk is fine. Damage there seems very limited. Add a comment though :)

+  },
   "systemIndicator": {
     "channel": "dev",
     "extension_types": ["extension", "legacy_packaged_app", "platform_app"]
   },
   "storage": {
     "channel": "stable",
     "extension_types": ["extension", "legacy_packaged_app", "platform_app"],
     "min_manifest_version": 2
   },
   "system.cpu": {
@@ skipping 177 matching lines @@
     // Only allowed for whitelisted extensions until all the caveats are
     // addressed. Tracked in crbug/285151.
     "channel": "stable",
     "extension_types": ["extension"],
     "location": "component",
     "whitelist": [
       "D519188F86D9ACCEE0412007B227D9936EB9676B"  // GAIA Component Extension
     ]
   }]
 }