Reland of Improves focus/activation for aura-mus and DesktopNativeWidgetAura

Reland of Improves focus/activation for aura-mus and DesktopNativeWidgetAura (patchset #1 id:1 of https://codereview.chromium.org/2480273003/ )

Reason for revert:
Relanding this. The real culprit was https://codereview.chromium.org/2484203002/

Original issue's description:
> Revert of Improves focus/activation for aura-mus and DesktopNativeWidgetAura (patchset #1 id:1 of https://codereview.chromium.org/2483063002/ )
>
> Reason for revert:
> Seems to cause heap use after free on tests in Mac Asan 10.9.
>
> https://build.chromium.org/p/chromium.memory/builders/Mac%20ASan%2064%20Tests%20%281%29/builds/23999
>
> FocusTraversalTest.TraversalWithInvisibleViews
> FocusTraversalTest.NormalTraversalMac
> FocusTraversalTest.PaneTraversal
> FocusTraversalTest.FullKeyboardToggle
> FocusTraversalTest.TraversalWithNonEnabledViews
> FocusTraversalTest.NormalTraversal
>
> Original issue's description:
> > Improves focus/activation for aura-mus and DesktopNativeWidgetAura
> >
> > When using DesktopNativeWidgetAura there is a FocusClient per
> > DesktopNativeWidgetAura. Aura-mus was assuming there would be a global
> > FocusClient, but that's painful for DesktopNativeWidgetAura. So, this
> > makes aura-mus work with multiple FocusClients. Specifically this does
> > the following:
> >
> > Env gets a function to track the active FocusClient. Env doesn't
> > maintain this, it's assuming others will. In particular
> > DesktopWindowTreeHostMus and WindowTreeClient makes call to it.
> >
> > Focus logic moves out of WindowTreeClient and into
> > FocusSynchronizer. FocusSynchronizer adds itself as an EnvObserserver
> > to track when the active FocusClient changes so that it can update the
> > server.
> >
> > BUG=660994
> > TEST=covered by tests
> > R=ben@chromium.org
> >
> > Committed: https://crrev.com/3b82d5c5307d2ae7e25243efa006eb13fd631d92
> > Cr-Commit-Position: refs/heads/master@{#430464}
>
> TBR=ben@chromium.org,sky@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=660994
>
> Committed: https://crrev.com/3e652a8cbbe2991e34e65cbb7635bc3d89db19f4
> Cr-Commit-Position: refs/heads/master@{#430556}

TBR=ben@chromium.org,sky@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=660994
Committed: https://crrev.com/df1ac6bd6c88b6861c86fc6b3148930d0948b92d
Cr-Commit-Position: refs/heads/master@{#430620}

[perkj_chrome, 2016-11-08 15:35:37]

The CQ bit was checked by perkj@chromium.org

[perkj_chrome, 2016-11-08 15:35:37]

Created Reland of Improves focus/activation for aura-mus and
DesktopNativeWidgetAura

[commit-bot: I haz the power, 2016-11-08 15:35:48]

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, 2016-11-08 15:37:53]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-11-08 15:41:59]

Description was changed from

==========
Reland of Improves focus/activation for aura-mus and DesktopNativeWidgetAura
(patchset #1 id:1 of https://codereview.chromium.org/2480273003/ )

Reason for revert:
Relanding this. The real culprit was https://codereview.chromium.org/2484203002/

Original issue's description:
> Revert of Improves focus/activation for aura-mus and DesktopNativeWidgetAura
(patchset #1 id:1 of https://codereview.chromium.org/2483063002/ )
> 
> Reason for revert:
> Seems to cause heap use after free on tests in Mac Asan 10.9.
> 
>
https://build.chromium.org/p/chromium.memory/builders/Mac%20ASan%2064%20Tests...
> 
> FocusTraversalTest.TraversalWithInvisibleViews
> FocusTraversalTest.NormalTraversalMac
> FocusTraversalTest.PaneTraversal
> FocusTraversalTest.FullKeyboardToggle
> FocusTraversalTest.TraversalWithNonEnabledViews
> FocusTraversalTest.NormalTraversal
> 
> Original issue's description:
> > Improves focus/activation for aura-mus and DesktopNativeWidgetAura
> >
> > When using DesktopNativeWidgetAura there is a FocusClient per
> > DesktopNativeWidgetAura. Aura-mus was assuming there would be a global
> > FocusClient, but that's painful for DesktopNativeWidgetAura. So, this
> > makes aura-mus work with multiple FocusClients. Specifically this does
> > the following:
> >
> > Env gets a function to track the active FocusClient. Env doesn't
> > maintain this, it's assuming others will. In particular
> > DesktopWindowTreeHostMus and WindowTreeClient makes call to it.
> >
> > Focus logic moves out of WindowTreeClient and into
> > FocusSynchronizer. FocusSynchronizer adds itself as an EnvObserserver
> > to track when the active FocusClient changes so that it can update the
> > server.
> >
> > BUG=660994
> > TEST=covered by tests
> > R=ben@chromium.org
> >
> > Committed: https://crrev.com/3b82d5c5307d2ae7e25243efa006eb13fd631d92
> > Cr-Commit-Position: refs/heads/master@{#430464}
> 
> TBR=ben@chromium.org,sky@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=660994
> 
> Committed: https://crrev.com/3e652a8cbbe2991e34e65cbb7635bc3d89db19f4
> Cr-Commit-Position: refs/heads/master@{#430556}

TBR=ben@chromium.org,sky@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=660994
==========

to

==========
Reland of Improves focus/activation for aura-mus and DesktopNativeWidgetAura
(patchset #1 id:1 of https://codereview.chromium.org/2480273003/ )

Reason for revert:
Relanding this. The real culprit was https://codereview.chromium.org/2484203002/

Original issue's description:
> Revert of Improves focus/activation for aura-mus and DesktopNativeWidgetAura
(patchset #1 id:1 of https://codereview.chromium.org/2483063002/ )
>
> Reason for revert:
> Seems to cause heap use after free on tests in Mac Asan 10.9.
>
>
https://build.chromium.org/p/chromium.memory/builders/Mac%20ASan%2064%20Tests...
>
> FocusTraversalTest.TraversalWithInvisibleViews
> FocusTraversalTest.NormalTraversalMac
> FocusTraversalTest.PaneTraversal
> FocusTraversalTest.FullKeyboardToggle
> FocusTraversalTest.TraversalWithNonEnabledViews
> FocusTraversalTest.NormalTraversal
>
> Original issue's description:
> > Improves focus/activation for aura-mus and DesktopNativeWidgetAura
> >
> > When using DesktopNativeWidgetAura there is a FocusClient per
> > DesktopNativeWidgetAura. Aura-mus was assuming there would be a global
> > FocusClient, but that's painful for DesktopNativeWidgetAura. So, this
> > makes aura-mus work with multiple FocusClients. Specifically this does
> > the following:
> >
> > Env gets a function to track the active FocusClient. Env doesn't
> > maintain this, it's assuming others will. In particular
> > DesktopWindowTreeHostMus and WindowTreeClient makes call to it.
> >
> > Focus logic moves out of WindowTreeClient and into
> > FocusSynchronizer. FocusSynchronizer adds itself as an EnvObserserver
> > to track when the active FocusClient changes so that it can update the
> > server.
> >
> > BUG=660994
> > TEST=covered by tests
> > R=ben@chromium.org
> >
> > Committed: https://crrev.com/3b82d5c5307d2ae7e25243efa006eb13fd631d92
> > Cr-Commit-Position: refs/heads/master@{#430464}
>
> TBR=ben@chromium.org,sky@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=660994
>
> Committed: https://crrev.com/3e652a8cbbe2991e34e65cbb7635bc3d89db19f4
> Cr-Commit-Position: refs/heads/master@{#430556}

TBR=ben@chromium.org,sky@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=660994

Committed: https://crrev.com/df1ac6bd6c88b6861c86fc6b3148930d0948b92d
Cr-Commit-Position: refs/heads/master@{#430620}
==========

[commit-bot: I haz the power, 2016-11-08 15:42:00]

Patchset 1 (id:??) landed as
https://crrev.com/df1ac6bd6c88b6861c86fc6b3148930d0948b92d
Cr-Commit-Position: refs/heads/master@{#430620}