Add ImageDecoder.Source for resources

Bug: 74545298
Test: Ibc283c2e8aee999e951de51f3a43b581a765aaf5

Although resources can already be accessed with ContentResolver + URI,
this allows a simple method to do the same.

Change-Id: I1bf698f36d5540f6de7cb9957e4223123d0f4331
2 files changed