[Chromoting] Move app-specific code out of remoting.js
After this cl, the last remaining reference to remoting.AppMode in AppRemoting is in app_remoting.js. That will be addressed in a followup cl.
Move the following out of remoting.js and into app-specific locations:
* remoting.signOut (into crd_event_handlers.js)
* remoting.showErrorMessage (into desktop_remoting.js)
* isWindowed_ (into desktop_remoting.js)
* remoting.promptClose (into desktop_remoting.js)
* remoting.isMe2MeInstallable (into local_host_section.js)
Rename Delegate.signInFailed -> Delegate.handleAuthError
Add Application.onAuthError to call Delegate.handleAuthError
Change references to global remoting.showErrorMessage to remoting.app.onAuthError
BUG=
Review URL: https://codereview.chromium.org/
1020743002
Cr-Commit-Position: refs/heads/master@{#321502}