Replace pinch scrollbars with regular scrollbars.

Replace pinch scrollbars with regular scrollbars.

This patch makes the visual-viewport-managed scrollbars exclusive to
Android and improves normal scrollbars to be usable during pinch as follows:

1. Attach the scrollbar layers to the visual viewport, so they're always
   onscreen as you zoom in (as already shipped on Mac).
2. Set the container layer to the inner clip layer, so that the size and
   position of the thumb reflects the sum of the two viewports,
   instead of just the layout viewport.

Note that result of these changes is visually indistiguishable at
minimum page scale.  It only improves the behavior when zoomed in.

BUG=523056
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=201285

[aelias_OOO_until_Jul13, 2015-08-25 00:09:32]

aelias@chromium.org changed reviewers:
+ skobes@chromium.org

[aelias_OOO_until_Jul13, 2015-08-25 00:09:58]

Hi skobes@, PTAL.

[skobes, 2015-08-25 00:19:01]

https://codereview.chromium.org/1308053003/diff/20001/Source/core/frame/Frame...
File Source/core/frame/FrameView.cpp (right):

https://codereview.chromium.org/1308053003/diff/20001/Source/core/frame/Frame...
Source/core/frame/FrameView.cpp:679: GraphicsLayer*
FrameView::layerForScrollbarContainer() const
Do we need a similar override in DeprecatedPaintLayerScrollableArea when
--root-layer-scrolls is enabled?

https://codereview.chromium.org/1308053003/diff/20001/Source/core/frame/Frame...
Source/core/frame/FrameView.cpp:3247: newHasHorizontalScrollbar =
newHasVerticalScrollbar = true;
Why is this needed?

[aelias_OOO_until_Jul13, 2015-08-25 02:50:27]

https://codereview.chromium.org/1308053003/diff/20001/Source/core/frame/Frame...
File Source/core/frame/FrameView.cpp (right):

https://codereview.chromium.org/1308053003/diff/20001/Source/core/frame/Frame...
Source/core/frame/FrameView.cpp:679: GraphicsLayer*
FrameView::layerForScrollbarContainer() const
On 2015/08/25 at 00:19:01, skobes wrote:
> Do we need a similar override in DeprecatedPaintLayerScrollableArea when
--root-layer-scrolls is enabled?

Done, and I also fixed the layer attachment with that flag.

https://codereview.chromium.org/1308053003/diff/20001/Source/core/frame/Frame...
Source/core/frame/FrameView.cpp:3247: newHasHorizontalScrollbar =
newHasVerticalScrollbar = true;
On 2015/08/25 at 00:19:01, skobes wrote:
> Why is this needed?

So that scrollbars are shown when zooming in (particularly on Android), even if
they weren't needed at minimum scale.  Note that CC is smart about hiding a
scrollbar if that orientation is nonscrollable.

[skobes, 2015-08-25 03:28:06]

The CQ bit was checked by skobes@chromium.org

[skobes, 2015-08-25 03:28:07]

lgtm

[commit-bot: I haz the power, 2015-08-25 03:28:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1308053003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1308053003/40001

[commit-bot: I haz the power, 2015-08-25 03:36:28]

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

[commit-bot: I haz the power, 2015-08-25 03:36:29]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[aelias_OOO_until_Jul13, 2015-08-26 04:47:47]

aelias@chromium.org changed reviewers:
+ rbyers@chromium.org

[aelias_OOO_until_Jul13, 2015-08-26 04:47:48]

Adding rbyers@ for OWNERS for small ScrollableArea API change.

https://codereview.chromium.org/1308053003/diff/20001/Source/core/frame/Frame...
File Source/core/frame/FrameView.cpp (right):

https://codereview.chromium.org/1308053003/diff/20001/Source/core/frame/Frame...
Source/core/frame/FrameView.cpp:3247: newHasHorizontalScrollbar =
newHasVerticalScrollbar = true;
On 2015/08/25 at 02:50:27, aelias wrote:
> On 2015/08/25 at 00:19:01, skobes wrote:
> > Why is this needed?
> 
> So that scrollbars are shown when zooming in (particularly on Android), even
if they weren't needed at minimum scale.  Note that CC is smart about hiding a
scrollbar if that orientation is nonscrollable.

Unfortunately, this approach turned out to be flaky (and broken in a different
way when --root-layer-scrolls), so I deleted this line and ended up bringing
back the VisualViewport scrollbars, which are now Android-only scrollbars.  The
VisualViewport scrollbar deletion should be more feasible when
--root-layer-scrolls is shipped.

[Rick Byers, 2015-08-26 14:37:52]

On 2015/08/26 04:47:48, aelias wrote:
> Adding rbyers@ for OWNERS for small ScrollableArea API change.

ScrollableArea.h LGTM

> 
>
https://codereview.chromium.org/1308053003/diff/20001/Source/core/frame/Frame...
> File Source/core/frame/FrameView.cpp (right):
> 
>
https://codereview.chromium.org/1308053003/diff/20001/Source/core/frame/Frame...
> Source/core/frame/FrameView.cpp:3247: newHasHorizontalScrollbar =
> newHasVerticalScrollbar = true;
> On 2015/08/25 at 02:50:27, aelias wrote:
> > On 2015/08/25 at 00:19:01, skobes wrote:
> > > Why is this needed?
> > 
> > So that scrollbars are shown when zooming in (particularly on Android), even
> if they weren't needed at minimum scale.  Note that CC is smart about hiding a
> scrollbar if that orientation is nonscrollable.
> 
> Unfortunately, this approach turned out to be flaky (and broken in a different
> way when --root-layer-scrolls), so I deleted this line and ended up bringing
> back the VisualViewport scrollbars, which are now Android-only scrollbars. 
The
> VisualViewport scrollbar deletion should be more feasible when
> --root-layer-scrolls is shipped.

[skobes, 2015-08-26 18:21:32]

lgtm

I assume you've checked that devtools mobile emulation shows the Android-only
scrollbars correctly?

https://codereview.chromium.org/1308053003/diff/140001/Source/core/frame/Fram...
File Source/core/frame/FrameView.h (right):

https://codereview.chromium.org/1308053003/diff/140001/Source/core/frame/Fram...
Source/core/frame/FrameView.h:272: bool visualViewportSuppliesScrollbars()
const;
nit: can this be private?

[aelias_OOO_until_Jul13, 2015-08-27 03:11:34]

I needed to make a few more changes in theming and an extra attachment call to
make them show up in devtools emulaton, but they work now (and now have the same
look as Android's scrollbars).

https://codereview.chromium.org/1308053003/diff/140001/Source/core/frame/Fram...
File Source/core/frame/FrameView.h (right):

https://codereview.chromium.org/1308053003/diff/140001/Source/core/frame/Fram...
Source/core/frame/FrameView.h:272: bool visualViewportSuppliesScrollbars()
const;
On 2015/08/26 at 18:21:32, skobes wrote:
> nit: can this be private?

Done.

[aelias_OOO_until_Jul13, 2015-08-27 03:11:41]

The CQ bit was checked by aelias@chromium.org

[aelias_OOO_until_Jul13, 2015-08-27 03:11:41]

The patchset sent to the CQ was uploaded after l-g-t-m from skobes@chromium.org,
rbyers@chromium.org
Link to the patchset: https://codereview.chromium.org/1308053003/#ps180001
(title: "Rebase")

[commit-bot: I haz the power, 2015-08-27 03:11:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1308053003/180001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1308053003/180001

[commit-bot: I haz the power, 2015-08-27 04:29:00]

Committed patchset #10 (id:180001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=201285

[aelias_OOO_until_Jul13, 2015-08-27 20:08:39]

A revert of this CL (patchset #10 id:180001) has been created in
https://codereview.chromium.org/1318603005/ by aelias@chromium.org.

The reason for reverting is: Introduced ChromeDriver devtools mobile emulation
crash https://code.google.com/p/chromedriver/issues/detail?id=1205.