[SyncFS] Refine RemoteToLocalSyncer resolver

 * Unify analyzing part and dispatching part
 * Complete missing cases handling
 * Add DCHECKs

BUG=240165

Review URL: https://codereview.chromium.org/58953003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234370 0039d316-1c4b-4281-b951-d872f2087c98
Don't call DidChangeView on PPP_Instance after Delete() has been called.

It's possible for the plugin element to be destroyed before the renderer
releases its reference to the plugin instance. This results in
|instance_interface_| being reset to NULL and crashing if SendDidChangeView
is called afterward.

BUG=314073

Review URL: https://codereview.chromium.org/62493006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234371 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234371
adding mcasas@ to webrtc_media watchlist

Review URL: https://codereview.chromium.org/64223005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234372 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234372