Don't cancel out scroll offset when calculating the clip rectangle for multicol.

Don't cancel out scroll offset when calculating the clip rectangle for multicol.

We still want the clip rect to be relative to the multicol container, but we
cannot get there by using the location() of the flow thread's PaintLayer,
because then we'll then cancel out the scroll offset that's also baked into
offsetOfPaginationLayerFromRoot.

This CL will cause paint/invalidation/paged-with-overflowing-block-rl.html to
regress, but it turned out that it just passed by accident anyway. Having that
test broken is way less serious than barely being able to scroll at all in a
regular multicol container.

BUG=674640
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2643123004
Cr-Commit-Position: refs/heads/master@{#445478}
(cherry picked from commit ccde605b5967c796069c4208227f088b62bc7483)

Review-Url: https://codereview.chromium.org/2651713006 .
Cr-Commit-Position: refs/branch-heads/2987@{#71}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed: https://chromium.googlesource.com/chromium/src/+/12a56329208e800d464f2692db6edb2505c262b9

[mstensho (USE GERRIT), 2017-01-24 20:23:33]

Description was changed from

==========
Don't cancel out scroll offset when calculating the clip rectangle for multicol.

We still want the clip rect to be relative to the multicol container, but we
cannot get there by using the location() of the flow thread's PaintLayer,
because then we'll then cancel out the scroll offset that's also baked into
offsetOfPaginationLayerFromRoot.

This CL will cause paint/invalidation/paged-with-overflowing-block-rl.html to
regress, but it turned out that it just passed by accident anyway. Having that
test broken is way less serious than barely being able to scroll at all in a
regular multicol container.

BUG=674640
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2643123004
Cr-Commit-Position: refs/heads/master@{#445478}
(cherry picked from commit ccde605b5967c796069c4208227f088b62bc7483)
==========

to

==========
Don't cancel out scroll offset when calculating the clip rectangle for multicol.

We still want the clip rect to be relative to the multicol container, but we
cannot get there by using the location() of the flow thread's PaintLayer,
because then we'll then cancel out the scroll offset that's also baked into
offsetOfPaginationLayerFromRoot.

This CL will cause paint/invalidation/paged-with-overflowing-block-rl.html to
regress, but it turned out that it just passed by accident anyway. Having that
test broken is way less serious than barely being able to scroll at all in a
regular multicol container.

BUG=674640
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2643123004
Cr-Commit-Position: refs/heads/master@{#445478}
(cherry picked from commit ccde605b5967c796069c4208227f088b62bc7483)

Review-Url: https://codereview.chromium.org/2651713006 .
Cr-Commit-Position: refs/branch-heads/2987@{#71}
Cr-Branched-From:
ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed:
https://chromium.googlesource.com/chromium/src/+/12a56329208e800d464f2692db6e...
==========

[mstensho (USE GERRIT), 2017-01-24 20:23:35]

Committed patchset #1 (id:1) manually as
12a56329208e800d464f2692db6edb2505c262b9 (tree was closed).