Allow icons in shared restables to be themed

Example
Google Drive's package  name: com.google.android.apps.docs
Google Drive's restable name: com.google.android.apps.docs.common

Before this patch we used resource table name to get the package info. For
app's like google drive this return a null package info and the icon would not be themed.

So instead of usnig the restable name, this patch creates a package name
in AssetManager that is set by getTopLevelResources.

Change-Id: Ic51b93f6c7ea0a32197682998c6d0aa36d774845
hide new AssetManager methods for themes

Change-Id: I9f5c6a432f9c2f3c1dd5bd9927c5e3fe3ddd1f93