The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/53d1a583d02610eca11732c9560ef2789139f4eb

commit 53d1a583d02610eca11732c9560ef2789139f4eb
Author: Qiang Xu <warx@google.com>
Date: Thu May 24 18:44:19 2018

arc: introduce searching app shortcuts in launcher

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}
[modify] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/ash/public/cpp/app_list/app_list_features.cc
[modify] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/ash/public/cpp/app_list/app_list_features.h
[modify] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/chrome/browser/about_flags.cc
[modify] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/chrome/browser/flag_descriptions.cc
[modify] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/chrome/browser/flag_descriptions.h
[modify] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/chrome/browser/ui/BUILD.gn
[add] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/chrome/browser/ui/app_list/search/arc/arc_app_shortcut_search_result.cc
[add] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/chrome/browser/ui/app_list/search/arc/arc_app_shortcut_search_result.h
[add] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/chrome/browser/ui/app_list/search/arc/arc_app_shortcuts_search_provider.cc
[add] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/chrome/browser/ui/app_list/search/arc/arc_app_shortcuts_search_provider.h
[add] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/chrome/browser/ui/app_list/search/arc/arc_app_shortcuts_search_provider_unittest.cc
[modify] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/chrome/browser/ui/app_list/search/search_controller_factory.cc
[modify] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/chrome/test/BUILD.gn
[modify] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/components/arc/common/app.mojom
[modify] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/components/arc/test/fake_app_instance.cc
[modify] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/components/arc/test/fake_app_instance.h
[modify] https://crrev.com/53d1a583d02610eca11732c9560ef2789139f4eb/tools/metrics/histograms/enums.xml

The remaining work is (1)  issue 856524  (2) UI based on specs

It would also be good to record some user metrics for this feature.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f70dc791c0f421c6ac340019a9721df97af0da8d

commit f70dc791c0f421c6ac340019a9721df97af0da8d
Author: Weidong Guo <weidongg@chromium.org>
Date: Thu Jul 12 18:56:00 2018

Introduce GetAppShortcutGlobalQueryItems mojo method

The original solution passing all available app shortcuts metadata to
Chrome has large latency because getting icons is expensive. This CL
proposes a new API that passes query and maxResults to Android, and
searching & results num throttling is done in Android as well.
Android side change is in ag/4432308.

Bug:  842947 
Test: manual test, latency is controlled in tens milliseconds

Change-Id: I48c168ffd56826c10a4b6d5befb995a087f4a0b2
Reviewed-on: https://chromium-review.googlesource.com/1117893
Reviewed-by: Luis Hector Chavez <lhchavez@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Yury Khmel <khmel@chromium.org>
Reviewed-by: Qiang Xu <warx@google.com>
Commit-Queue: Weidong Guo <weidongg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574653}
[modify] https://crrev.com/f70dc791c0f421c6ac340019a9721df97af0da8d/chrome/browser/ui/app_list/search/arc/arc_app_shortcuts_search_provider.cc
[modify] https://crrev.com/f70dc791c0f421c6ac340019a9721df97af0da8d/chrome/browser/ui/app_list/search/arc/arc_app_shortcuts_search_provider.h
[modify] https://crrev.com/f70dc791c0f421c6ac340019a9721df97af0da8d/chrome/browser/ui/app_list/search/arc/arc_app_shortcuts_search_provider_unittest.cc
[modify] https://crrev.com/f70dc791c0f421c6ac340019a9721df97af0da8d/chrome/browser/ui/app_list/search/search_controller_factory.cc
[modify] https://crrev.com/f70dc791c0f421c6ac340019a9721df97af0da8d/components/arc/common/app.mojom
[modify] https://crrev.com/f70dc791c0f421c6ac340019a9721df97af0da8d/components/arc/test/fake_app_instance.cc
[modify] https://crrev.com/f70dc791c0f421c6ac340019a9721df97af0da8d/components/arc/test/fake_app_instance.h

Ready to launch, closing the tracking bug