Fix smooth scroll overshooting when mouse held down in scrollbar track.

Fix smooth scroll overshooting when mouse held down in scrollbar track.

Scrollbar::autoscrollPressedPart now checks if the mouse is under the thumb's
eventual (target) position, rather than its current position.

BUG=578554
Committed: https://crrev.com/ef53ba38118cb84ed66bb9d9335e8b3a550865d6
Cr-Commit-Position: refs/heads/master@{#370285}

[skobes, 2016-01-19 21:15:01]

Patchset #2 (id:20001) has been deleted

[skobes, 2016-01-19 21:15:12]

Patchset #1 (id:1) has been deleted

[skobes, 2016-01-19 21:24:28]

Description was changed from

==========
Fix smooth scroll overshooting when mouse held down in scrollbar track.

BUG=578554
==========

to

==========
Fix smooth scroll overshooting when mouse held down in scrollbar track.

Scrollbar::autoscrollPressedPart now checks if the mouse is under the thumb's
final position, rather than its current position.

BUG=578554
==========

[skobes, 2016-01-19 21:24:57]

Description was changed from

==========
Fix smooth scroll overshooting when mouse held down in scrollbar track.

Scrollbar::autoscrollPressedPart now checks if the mouse is under the thumb's
final position, rather than its current position.

BUG=578554
==========

to

==========
Fix smooth scroll overshooting when mouse held down in scrollbar track.

Scrollbar::autoscrollPressedPart now checks if the mouse is under the thumb's
eventual (target) position, rather than its current position.

BUG=578554
==========

[skobes, 2016-01-19 22:16:11]

Patchset #1 (id:40001) has been deleted

[skobes, 2016-01-19 22:16:36]

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

[jbroman, 2016-01-19 22:39:12]

lgtm with a couple questions

https://codereview.chromium.org/1601303003/diff/60001/third_party/WebKit/Layo...
File
third_party/WebKit/LayoutTests/fast/scroll-behavior/smooth-scroll/track-scroll.html
(right):

https://codereview.chromium.org/1601303003/diff/60001/third_party/WebKit/Layo...
third_party/WebKit/LayoutTests/fast/scroll-behavior/smooth-scroll/track-scroll.html:17:
pageStep = Math.max(pageStep, innerHeight - 40);
Unfortunate to have this hard-coded in a layout test. I guess there's no easy
way around this?

https://codereview.chromium.org/1601303003/diff/60001/third_party/WebKit/Sour...
File third_party/WebKit/Source/platform/scroll/ScrollAnimatorBase.h (right):

https://codereview.chromium.org/1601303003/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/platform/scroll/ScrollAnimatorBase.h:74: virtual
FloatPoint desiredTargetPosition() const { return currentPosition(); }
It's not obvious to me why this definition makes sense for ScrollAnimatorMac.

[skobes, 2016-01-19 23:44:14]

https://codereview.chromium.org/1601303003/diff/60001/third_party/WebKit/Layo...
File
third_party/WebKit/LayoutTests/fast/scroll-behavior/smooth-scroll/track-scroll.html
(right):

https://codereview.chromium.org/1601303003/diff/60001/third_party/WebKit/Layo...
third_party/WebKit/LayoutTests/fast/scroll-behavior/smooth-scroll/track-scroll.html:17:
pageStep = Math.max(pageStep, innerHeight - 40);
On 2016/01/19 22:39:12, jbroman wrote:
> Unfortunate to have this hard-coded in a layout test. I guess there's no easy
> way around this?

In theory we could expose it through window.internals somehow, but that seems
like overkill.

It looks like fast/events/platform-wheelevent-paging-xy-in-scrolling-page.html
does this as well.

https://codereview.chromium.org/1601303003/diff/60001/third_party/WebKit/Sour...
File third_party/WebKit/Source/platform/scroll/ScrollAnimatorBase.h (right):

https://codereview.chromium.org/1601303003/diff/60001/third_party/WebKit/Sour...
third_party/WebKit/Source/platform/scroll/ScrollAnimatorBase.h:74: virtual
FloatPoint desiredTargetPosition() const { return currentPosition(); }
On 2016/01/19 22:39:12, jbroman wrote:
> It's not obvious to me why this definition makes sense for ScrollAnimatorMac.

The bug is specific to the non-Mac scroll animator, so this change preserves the
existing behavior on Mac.  I don't think ScrollAnimatorMac even stores the
target, so it wouldn't be useful for it to override this.

[jbroman, 2016-01-20 00:17:24]

lgtm

[skobes, 2016-01-20 00:33:04]

The CQ bit was checked by skobes@chromium.org

[commit-bot: I haz the power, 2016-01-20 00:38:58]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1601303003/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1601303003/60001

[commit-bot: I haz the power, 2016-01-20 01:08:34]

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

[commit-bot: I haz the power, 2016-01-20 01:08:34]

Try jobs failed on following builders:
  linux_chromium_chromeos_ozone_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_chromeos_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[skobes, 2016-01-20 01:27:17]

The CQ bit was checked by skobes@chromium.org

[commit-bot: I haz the power, 2016-01-20 01:30:09]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1601303003/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1601303003/60001

[commit-bot: I haz the power, 2016-01-20 02:39:34]

Description was changed from

==========
Fix smooth scroll overshooting when mouse held down in scrollbar track.

Scrollbar::autoscrollPressedPart now checks if the mouse is under the thumb's
eventual (target) position, rather than its current position.

BUG=578554
==========

to

==========
Fix smooth scroll overshooting when mouse held down in scrollbar track.

Scrollbar::autoscrollPressedPart now checks if the mouse is under the thumb's
eventual (target) position, rather than its current position.

BUG=578554
==========

[commit-bot: I haz the power, 2016-01-20 02:39:34]

Committed patchset #1 (id:60001)

[commit-bot: I haz the power, 2016-01-20 02:40:54]

Description was changed from

==========
Fix smooth scroll overshooting when mouse held down in scrollbar track.

Scrollbar::autoscrollPressedPart now checks if the mouse is under the thumb's
eventual (target) position, rather than its current position.

BUG=578554
==========

to

==========
Fix smooth scroll overshooting when mouse held down in scrollbar track.

Scrollbar::autoscrollPressedPart now checks if the mouse is under the thumb's
eventual (target) position, rather than its current position.

BUG=578554

Committed: https://crrev.com/ef53ba38118cb84ed66bb9d9335e8b3a550865d6
Cr-Commit-Position: refs/heads/master@{#370285}
==========

[commit-bot: I haz the power, 2016-01-20 02:40:55]

Patchset 1 (id:??) landed as
https://crrev.com/ef53ba38118cb84ed66bb9d9335e8b3a550865d6
Cr-Commit-Position: refs/heads/master@{#370285}