Revert of CrOS: Fix appearance of notification toasts when sliding out via gesture

Revert of CrOS: Fix appearance of notification toasts when sliding out via gesture (patchset #4 id:60001 of https://codereview.chromium.org/2849523005/ )

Reason for revert:
This appears to have broken message_center_unittests on chromium.win/Win10 Tests x64. See https://uberchromegw.corp.google.com/i/chromium.win/builders/Win10%20Tests%20x64/builds/11112/steps/message_center_unittests%20on%20Windows-10-10586 for one example.

Original issue's description:
> CrOS: Fix appearance of notification toasts when sliding out via gesture
> 
> This converts SlideOutView to SlideOutController, which provides all the
> same functionality but can be added to any view rather than just those
> that extend it.
> 
> It allows the target view to control the layer that's sliding out. For
> toasts, that is the widget's layer. For notifications inside the message
> center, that will continue to be the NotificationView itself.
> 
> BUG=716429
> 
> Review-Url: https://codereview.chromium.org/2849523005
> Cr-Commit-Position: refs/heads/master@{#468339}
> Committed: https://chromium.googlesource.com/chromium/src/+/3d7851ff607c370234e4f93ecf66727a8f8498d9

TBR=yoshiki@chromium.org,estade@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=716429
Review-Url: https://codereview.chromium.org/2850153003
Cr-Commit-Position: refs/heads/master@{#468394}
Committed: https://chromium.googlesource.com/chromium/src/+/ba5c53c9efbb48cd5f54de19e996b24e63f511db

[sky, 2017-05-01 20:14:35]

The CQ bit was checked by sky@chromium.org

[sky, 2017-05-01 20:14:36]

Created Revert of CrOS: Fix appearance of notification toasts when sliding out
via gesture

[commit-bot: I haz the power, 2017-05-01 20:15:25]

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, 2017-05-01 20:15:55]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1493669675998570, "parent_rev":
"b042a7e565df1572caa21084289f6e37db216684", "commit_rev":
"ba5c53c9efbb48cd5f54de19e996b24e63f511db"}

[commit-bot: I haz the power, 2017-05-01 20:16:12]

Description was changed from

==========
Revert of CrOS: Fix appearance of notification toasts when sliding out via
gesture (patchset #4 id:60001 of https://codereview.chromium.org/2849523005/ )

Reason for revert:
This appears to have broken message_center_unittests on chromium.win/Win10 Tests
x64. See
https://uberchromegw.corp.google.com/i/chromium.win/builders/Win10%20Tests%20...
for one example.

Original issue's description:
> CrOS: Fix appearance of notification toasts when sliding out via gesture
> 
> This converts SlideOutView to SlideOutController, which provides all the
> same functionality but can be added to any view rather than just those
> that extend it.
> 
> It allows the target view to control the layer that's sliding out. For
> toasts, that is the widget's layer. For notifications inside the message
> center, that will continue to be the NotificationView itself.
> 
> BUG=716429
> 
> Review-Url: https://codereview.chromium.org/2849523005
> Cr-Commit-Position: refs/heads/master@{#468339}
> Committed:
https://chromium.googlesource.com/chromium/src/+/3d7851ff607c370234e4f93ecf66...

TBR=yoshiki@chromium.org,estade@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=716429
==========

to

==========
Revert of CrOS: Fix appearance of notification toasts when sliding out via
gesture (patchset #4 id:60001 of https://codereview.chromium.org/2849523005/ )

Reason for revert:
This appears to have broken message_center_unittests on chromium.win/Win10 Tests
x64. See
https://uberchromegw.corp.google.com/i/chromium.win/builders/Win10%20Tests%20...
for one example.

Original issue's description:
> CrOS: Fix appearance of notification toasts when sliding out via gesture
> 
> This converts SlideOutView to SlideOutController, which provides all the
> same functionality but can be added to any view rather than just those
> that extend it.
> 
> It allows the target view to control the layer that's sliding out. For
> toasts, that is the widget's layer. For notifications inside the message
> center, that will continue to be the NotificationView itself.
> 
> BUG=716429
> 
> Review-Url: https://codereview.chromium.org/2849523005
> Cr-Commit-Position: refs/heads/master@{#468339}
> Committed:
https://chromium.googlesource.com/chromium/src/+/3d7851ff607c370234e4f93ecf66...

TBR=yoshiki@chromium.org,estade@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=716429

Review-Url: https://codereview.chromium.org/2850153003
Cr-Commit-Position: refs/heads/master@{#468394}
Committed:
https://chromium.googlesource.com/chromium/src/+/ba5c53c9efbb48cd5f54de19e996...
==========

[commit-bot: I haz the power, 2017-05-01 20:16:14]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/ba5c53c9efbb48cd5f54de19e996...