Add ability to have active window autohide shelf

Add ability to have active window autohide shelf

* Actual implementation of ShellSurface.setSystemUiVisibility
* Add hide_shelf_when_active_ flag to window_state
which the ShelfLayoutManager uses to determine if
the currently active window should autohide the shelf.
* Update flag accordingly from ShellSurface

BUG=705723
TEST=New unit tests, and also verify that using the
implementation from Android correctly autohides the shelf
for the active Android window.

Add set_systemui_visibility to wayland

Review-Url: https://codereview.chromium.org/2782223002
Cr-Commit-Position: refs/heads/master@{#460907}
(cherry picked from commit 74669cbfbef72bde5abdecb18e9c7920cca51419)

Review-Url: https://codereview.chromium.org/2790943003 .
Cr-Commit-Position: refs/branch-heads/3029@{#520}
Cr-Branched-From: 939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed: https://chromium.googlesource.com/chromium/src/+/d1c338b6a03a4fd3bdf05f57b4796ba6a8137f52

[oshima, 2017-03-31 21:53:09]

Description was changed from

==========
Add ability to have active window autohide shelf

* Actual implementation of ShellSurface.setSystemUiVisibility
* Add hide_shelf_when_active_ flag to window_state
which the ShelfLayoutManager uses to determine if
the currently active window should autohide the shelf.
* Update flag accordingly from ShellSurface

BUG=705723
TEST=New unit tests, and also verify that using the
implementation from Android correctly autohides the shelf
for the active Android window.

Add set_systemui_visibility to wayland

Review-Url: https://codereview.chromium.org/2782223002
Cr-Commit-Position: refs/heads/master@{#460907}
(cherry picked from commit 74669cbfbef72bde5abdecb18e9c7920cca51419)
==========

to

==========
Add ability to have active window autohide shelf

* Actual implementation of ShellSurface.setSystemUiVisibility
* Add hide_shelf_when_active_ flag to window_state
which the ShelfLayoutManager uses to determine if
the currently active window should autohide the shelf.
* Update flag accordingly from ShellSurface

BUG=705723
TEST=New unit tests, and also verify that using the
implementation from Android correctly autohides the shelf
for the active Android window.

Add set_systemui_visibility to wayland

Review-Url: https://codereview.chromium.org/2782223002
Cr-Commit-Position: refs/heads/master@{#460907}
(cherry picked from commit 74669cbfbef72bde5abdecb18e9c7920cca51419)

Review-Url: https://codereview.chromium.org/2790943003 .
Cr-Commit-Position: refs/branch-heads/3029@{#520}
Cr-Branched-From:
939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed:
https://chromium.googlesource.com/chromium/src/+/d1c338b6a03a4fd3bdf05f57b479...
==========

[oshima, 2017-03-31 21:53:10]

Committed patchset #1 (id:1) manually as
d1c338b6a03a4fd3bdf05f57b4796ba6a8137f52.