Non-composited, fixed position should trigger main thread scrolling

Non-composited, fixed position should trigger main thread scrolling

In a recent change, I broke the logic for determining whether fixed position
elements should trigger main thread scrolling. This CL fixes the logic to
trigger main thread scrolling if we have fixed position elements that lack
composited layers.

R=vollick@chromium.org
BUG=402359
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=180226

[Ian Vollick, 2014-08-13 22:22:00]

lgtm.

https://codereview.chromium.org/465333004/diff/1/Source/core/page/scrolling/S...
File Source/core/page/scrolling/ScrollingCoordinator.cpp (right):

https://codereview.chromium.org/465333004/diff/1/Source/core/page/scrolling/S...
Source/core/page/scrolling/ScrollingCoordinator.cpp:894: // Whether the
RenderLayer scrolls wth the viewport is a tree-depenent
with.

[abarth-chromium, 2014-08-13 23:06:13]

The CQ bit was checked by abarth@chromium.org

[commit-bot: I haz the power, 2014-08-13 23:07:02]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/abarth@chromium.org/465333004/20001

[commit-bot: I haz the power, 2014-08-14 03:09:46]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_chromium_gn_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_chromium_gn_rel/bu...)

[abarth-chromium, 2014-08-14 03:49:56]

Committed patchset #2 manually as 180226 (presubmit successful).