MacViews: Make window content views layer-backed.

MacViews: Make window content views layer-backed.

This lets the window clip content to its rounded corners (see
views_examples_with_content_exe). Also, to quote erikchen@:

> it's important that the content view is layer backed - it affects some
> flags within appkit

[Sidney San Martín, 2017-01-12 23:54:40]

Description was changed from

==========
MacViews: Make the window's content view layer-backed.

This lets the window clip content to its rounded corners (see
views_examples_with_content_exe). Also, to quote erikchen@:

> it's important that the content view is layer backed - it affects some
> flags within appkit
==========

to

==========
MacViews: Make window content views layer-backed.

This lets the window clip content to its rounded corners (see
views_examples_with_content_exe). Also, to quote erikchen@:

> it's important that the content view is layer backed - it affects some
> flags within appkit
==========

[Sidney San Martín, 2017-01-12 23:56:20]

sdy@chromium.org changed reviewers:
+ tapted@chromium.org

[Sidney San Martín, 2017-01-12 23:56:21]

The first thing I noticed in views_examples_with_content_exe was the content
poking out of the window corners :).

AFAIK we want layer backing everywhere; let me know if not.

[Sidney San Martín, 2017-01-12 23:56:25]

The CQ bit was checked by sdy@chromium.org

[commit-bot: I haz the power, 2017-01-12 23:58:28]

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, 2017-01-12 23:58:29]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-01-12 23:58:30]

No L-G-T-M from a valid reviewer yet. 
CQ run can only be started by full committers or once the patch has
received an L-G-T-M from a full committer.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[Sidney San Martín, 2017-01-12 23:58:53]

The CQ bit was checked by sdy@chromium.org to run a CQ dry run

[Sidney San Martín, 2017-01-12 23:59:12]

On 2017/01/12 23:58:30, commit-bot: I haz the power wrote:
> No L-G-T-M from a valid reviewer yet. 
> CQ run can only be started by full committers or once the patch has
> received an L-G-T-M from a full committer.
> Even if an L-G-T-M may have been provided, it was from a non-committer,
> _not_ a full super star committer.
> See http://www.chromium.org/getting-involved/become-a-committer
> Note that this has nothing to do with OWNERS files.

(Sorry, that was supposed to be a dry run.)

[commit-bot: I haz the power, 2017-01-13 00:00:58]

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

[tapted, 2017-01-13 00:22:37]

https://codereview.chromium.org/2622083007/diff/1/ui/views/cocoa/native_widge...
File ui/views/cocoa/native_widget_mac_nswindow.mm (right):

https://codereview.chromium.org/2622083007/diff/1/ui/views/cocoa/native_widge...
ui/views/cocoa/native_widget_mac_nswindow.mm:44:
static_cast<NSView*>(self.contentView).wantsLayer = YES;
ooh neat - I think this might fix http://crbug.com/649354 ? (wdyt - I'm not sure
if I can repro that.. but if(yes) can you cite that bug here?)  At the very
least it fixes the task manager not having rounded corners, and some resize
artifacts related to that \o/ - I can make a crbug for that if 649354 doesn't
fit.

But I think there's a downside -- this will need to allocate an additional
window-sized texture. So, I think there's no point doing this for fully
transparent windows. The best place for this might be in
bridged_native_widget.mm, with

  } else {
    [[window_ contentView] setWantsLayer:YES];
  }

towards the end of BridgedNativeWidget::CreateLayer()

This will happen after BridgedNativeWidget::SetRootView(..) which may replace
the windows' contentView.


Another approach might be to check for NSTexturedBackgroundWindowMask since
they're the ones AppKit promises to give rounded bottom corners to.

(but in either case, I think BridgedNativeWidget::CreateLayer is the right place
for it -- it seems like a quirk that this manages to work, since I'm pretty sure
SetRootView() happens after the initializer here, and it should be replacing the
contentView with a new one)

[commit-bot: I haz the power, 2017-01-13 01:22:42]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-01-13 01:22:45]

Dry run: Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)