Remove obsolete code left over from the system process
None of this is necessary now that the activity is running
in a normal application process. The 'name-based' version of
getSharedPreferences works fine.
Bug: 300157408
Flag: EXEMPT
Test: manually; share content, long-press to pin/unpin;
verify across usages and reboots
Change-Id: Id056cd377babf397b323b40c52614cd326d5c79e
IntentResolver provides the implementation for Intent ACTION_CHOOSER
See also: ShareCompat.IntentBuilder