Extract shortcuts loading logic from ChooserActivity

Extract shortcut loading logic from ChooserActivity into a new class
mostly as-is. Major changes:
- run the logic on a background executor and deliver the result on the
  main thread;
- replace dependencies from ChooserListAdapter with the data it
  provided.
A number of tests thap previusly used
ChooserListAdapter#addServiceResults to provide shortcut results into
the view are updated and re-enabled.

Re-introduction of ag/20236439

Fix: 259462188
Test: manual tests
Test: atest IntentResolverUnitTests
Change-Id: I2555c3e486b9a443c5101bbda33b5b214c959b0f

0 files changed, 0 insertions, 0 deletions