Copy Chromium extension message implementation

We need pass application info from browser process to renderer, so we will
borrow ExtensionMsg_Loaded message implementation from Chromium.
application/common/application_messages.* are copied from
chrome/common/extensions/extension_messages.*
Add ApplicationRendererController to handle application launched message

The launched application info will be serialized and sent to
ApplicationRendererController by ApplicationProcessManager. The
ApplicationRendererController will be created as a singleton for application
native module access.
Add application extension skeleton and getManifest API implementation

application.getManifest() API will return a running application's manifest
object synchronously. Ref to:
https://developer.chrome.com/apps/runtime.html#method-getManifest.
Add application API browser test for getManifest