Mac: Update scrollbar size and input position during impl-overscroll

Mac: Update scrollbar size and input position during impl-overscroll

Hook up WebViewImpl::applyViewportDeltas to send the elastic overscroll
delta to the FrameView, which tracks the current elastic overscroll, 
and is queried for the delta in Widget's convertHitPointToWindow helper
function.

Note that this is in contrast to the page scale factor, which is
tracked in Page's FrameHost's PinchViewport.

Push the current elastic overscroll down to the FrameView's scrollbars,
and invalidate them when the value changes. Plumb the setter and getter
functions through Scrollbar, ScrollbarThemeClient, and WebScrollbar, so
that the value may be accessed in ScrollbarTheme::thumbLength.

BUG=133097
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=187661

[ccameron, 2014-12-22 23:21:25]

ccameron@chromium.org changed reviewers:
+ kbr@chromium.org

[ccameron, 2014-12-22 23:26:46]

ccameron@chromium.org changed reviewers:
+ bokan@chromium.org

[ccameron, 2014-12-22 23:26:47]

Relatively simple plumbing patch.

Adding kbr for OWNER of core+platform+web.

Adding bokan WRT placing of overscroll in FrameView v hanging off of pinch
virtual viewport.

[Ken Russell (switch to Gerrit), 2014-12-22 23:46:08]

LGTM overall.

https://codereview.chromium.org/819953002/diff/60001/Source/platform/scroll/S...
File Source/platform/scroll/ScrollbarTheme.cpp (right):

https://codereview.chromium.org/819953002/diff/60001/Source/platform/scroll/S...
Source/platform/scroll/ScrollbarTheme.cpp:278: // thread overscroll mode (first)
// and then adding the result from
Reformat this comment.

https://codereview.chromium.org/819953002/diff/60001/Source/platform/scroll/S...
Source/platform/scroll/ScrollbarTheme.cpp:280: // exclusive modes (determining
which mode is in use here will require lots
"modes are mutually exclusive"

https://codereview.chromium.org/819953002/diff/60001/Source/web/tests/WebInpu...
File Source/web/tests/WebInputEventConversionTest.cpp (right):

https://codereview.chromium.org/819953002/diff/60001/Source/web/tests/WebInpu...
Source/web/tests/WebInputEventConversionTest.cpp:746:
view->setElasticOverscroll(FloatSize(10, -20));
Please factor the FloatSize into a separate variable so the math's more obvious.

https://codereview.chromium.org/819953002/diff/60001/Source/web/tests/WebInpu...
Source/web/tests/WebInputEventConversionTest.cpp:761: EXPECT_EQ(30,
platformMouseBuilder.position().y());
Would be better if these constants referred to the FloatSize's elements above.

https://codereview.chromium.org/819953002/diff/60001/Source/web/tests/WebInpu...
Source/web/tests/WebInputEventConversionTest.cpp:784: EXPECT_EQ(5 +
pinchOffset.y() - 20, platformMouseBuilder.position().y());
In particular, it would be better if the "+10" and "-20" referred to the
elements of the FloatSize above.

[ccameron, 2014-12-22 23:57:23]

Thanks!

https://codereview.chromium.org/819953002/diff/60001/Source/platform/scroll/S...
File Source/platform/scroll/ScrollbarTheme.cpp (right):

https://codereview.chromium.org/819953002/diff/60001/Source/platform/scroll/S...
Source/platform/scroll/ScrollbarTheme.cpp:278: // thread overscroll mode (first)
// and then adding the result from
On 2014/12/22 23:46:08, Ken Russell wrote:
> Reformat this comment.

Done.

https://codereview.chromium.org/819953002/diff/60001/Source/platform/scroll/S...
Source/platform/scroll/ScrollbarTheme.cpp:280: // exclusive modes (determining
which mode is in use here will require lots
On 2014/12/22 23:46:08, Ken Russell wrote:
> "modes are mutually exclusive"

Done.

https://codereview.chromium.org/819953002/diff/60001/Source/web/tests/WebInpu...
File Source/web/tests/WebInputEventConversionTest.cpp (right):

https://codereview.chromium.org/819953002/diff/60001/Source/web/tests/WebInpu...
Source/web/tests/WebInputEventConversionTest.cpp:746:
view->setElasticOverscroll(FloatSize(10, -20));
On 2014/12/22 23:46:08, Ken Russell wrote:
> Please factor the FloatSize into a separate variable so the math's more
obvious.

Done.

https://codereview.chromium.org/819953002/diff/60001/Source/web/tests/WebInpu...
Source/web/tests/WebInputEventConversionTest.cpp:746:
view->setElasticOverscroll(FloatSize(10, -20));
On 2014/12/22 23:46:08, Ken Russell wrote:
> Please factor the FloatSize into a separate variable so the math's more
obvious.

Done.

https://codereview.chromium.org/819953002/diff/60001/Source/web/tests/WebInpu...
Source/web/tests/WebInputEventConversionTest.cpp:761: EXPECT_EQ(30,
platformMouseBuilder.position().y());
On 2014/12/22 23:46:08, Ken Russell wrote:
> Would be better if these constants referred to the FloatSize's elements above.

Done.

[dcheng, 2014-12-23 00:22:38]

dcheng@chromium.org changed reviewers:
+ dcheng@chromium.org

[dcheng, 2014-12-23 00:22:38]

public/ changes LGTM

[bokan, 2014-12-23 16:59:23]

lgtm

[bokan, 2014-12-23 17:02:26]

As a followup to our chat yesterday, with device emulation it is possible that
you'll have pinch zoom and overscroll, but I think this still works as long as
the compositor tries scrolling both viewports before sending overscroll deltas.
The way the overscroll layer is hooked up in CC I think that's the case.

[ccameron, 2014-12-23 18:29:44]

Thanks!

[ccameron, 2014-12-23 18:29:48]

The CQ bit was checked by ccameron@chromium.org

[commit-bot: I haz the power, 2014-12-23 18:30:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/819953002/100001

[commit-bot: I haz the power, 2014-12-23 20:55:36]

Committed patchset #6 (id:100001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=187661