[Merge-M53] arc: Fix Drag&Drop for PlayStore item from App List to Shelf.

[Merge-M53] arc: Fix Drag&Drop for PlayStore item from App List to Shelf.

PlayStore is special app that actually represents 2 apps in Chrome.
One is OptIn flow as native Platform App, second is Android Play
Store app itself. For user we represent them as one app and do
special mapping for Chrome shelf. This CL adds missing functionality
for correct mapping.

TEST=unit_tests
TEST=Manually on device with all combination, app was pinned or
     not before, App (PlayStore and OptIn) was running or not.
BUG=b/31556052
BUG=648285
TBR=reviewer@chromium.org
NOTRY=true
NOPRESUBMIT=true

Review-Url: https://codereview.chromium.org/2349263002
Cr-Commit-Position: refs/heads/master@{#419502}
(cherry picked from commit ffdbe6cd0e06ea88251bdbfaa484b8b53c8fb1b2)

[khmel, 2016-09-19 18:29:21]

The CQ bit was checked by khmel@chromium.org

[commit-bot: I haz the power, 2016-09-19 18:29:59]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-19 18:35:39]

Committed patchset #1 (id:1)