GitLab

changes:
- Add #enable-app-shortcut-search flag and develop behind it.
- Chrome side framework to support searching app shortcuts.
- Reuse GetAppShortcutItems mojo API. When specified |package_name| is empty, it
  is aimed on global query.

Video demo:
https://drive.google.com/file/d/14y70Bn0gFrZqmqJtsCS8xPLUEC0twFwh/view?usp=sharing
https://drive.google.com/file/d/1LUyzoX0dLpy3rkAx420oqznZEO9Lyyww/view?usp=sharing

Bug: 842947
Test: manual test with Android change
Change-Id: I8d6f62f12d215d464815dd4ff6c31c1e6af9e2c5
Reviewed-on: https://chromium-review.googlesource.com/1058681
Commit-Queue: Qiang Xu <warx@google.com>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Luis Hector Chavez <lhchavez@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561570}