Revert 182194

Revert 182194
> Fix issue 174250, crash when reloading packaged app.
> 
> When a shell window was closed, it wasn't removed from the registry immediately
> (it was removed in a callback from OnNativeClose, which happens a bit later.)
> This meant that when the app was loaded again, the window was still in the
> registry with a stale pointer to the old extension. ExtensionSettingsHandler
> was tickling this by iterating shell windows on extension load.
> 
> BUG=174250
> 
> 
> Review URL: https://chromiumcodereview.appspot.com/12210107

TBR=jeremya@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=182230