arc: Add splash screen for ARC++ Kiosk startup

arc: Add splash screen for ARC++ Kiosk startup

Implemented similar to App Launch Splash Screen that is used for Chrome Kiosk.

Splash screen is shown immediately after launching ARC++ Kiosk session
and destructed when app window is launched. This leads to no UI exposed,
except to sign in screen, splash screen and finally app window.

User can escape launching of the app by pressing Ctrl+Alt+S during the splash
screen.

Also fixes bug of restarting app few seconds after launch.

BUG=682778, 682780, 681111, 677310
TEST=Manual, Start ARC++ Kiosk sessions.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2649103006
Cr-Commit-Position: refs/heads/master@{#448075}
(cherry picked from commit af6c8bbf83b31deb1a772193dff2ff2871f4fbd7)

Review-Url: https://codereview.chromium.org/2691493002 .
Cr-Commit-Position: refs/branch-heads/2987@{#432}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed: https://chromium.googlesource.com/chromium/src/+/9a3e555a3952276620ae2274a6707ff49357ed0f

[Sergey Poromov, 2017-02-10 11:03:51]

Description was changed from

==========
arc: Add splash screen for ARC++ Kiosk startup

Implemented similar to App Launch Splash Screen that is used for Chrome Kiosk.

Splash screen is shown immediately after launching ARC++ Kiosk session
and destructed when app window is launched. This leads to no UI exposed,
except to sign in screen, splash screen and finally app window.

User can escape launching of the app by pressing Ctrl+Alt+S during the splash
screen.

Also fixes bug of restarting app few seconds after launch.

BUG=682778,682780,	681111,677310
TEST=Manual, Start ARC++ Kiosk sessions.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2649103006
Cr-Commit-Position: refs/heads/master@{#448075}
(cherry picked from commit af6c8bbf83b31deb1a772193dff2ff2871f4fbd7)
==========

to

==========
arc: Add splash screen for ARC++ Kiosk startup

Implemented similar to App Launch Splash Screen that is used for Chrome Kiosk.

Splash screen is shown immediately after launching ARC++ Kiosk session
and destructed when app window is launched. This leads to no UI exposed,
except to sign in screen, splash screen and finally app window.

User can escape launching of the app by pressing Ctrl+Alt+S during the splash
screen.

Also fixes bug of restarting app few seconds after launch.

BUG=682778,682780,	681111,677310
TEST=Manual, Start ARC++ Kiosk sessions.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2649103006
Cr-Commit-Position: refs/heads/master@{#448075}
(cherry picked from commit af6c8bbf83b31deb1a772193dff2ff2871f4fbd7)

Review-Url: https://codereview.chromium.org/2691493002 .
Cr-Commit-Position: refs/branch-heads/2987@{#432}
Cr-Branched-From:
ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed:
https://chromium.googlesource.com/chromium/src/+/9a3e555a3952276620ae2274a670...
==========

[Sergey Poromov, 2017-02-10 11:03:53]

Committed patchset #1 (id:1) manually as
9a3e555a3952276620ae2274a6707ff49357ed0f.