Shift flowthread-to-visual coordinate space conversion one level up in the tree.

Shift flowthread-to-visual coordinate space conversion one level up in the tree.

The conversion now takes place between the flow thread and its parent multicol
container, rather than between the flow thread and its children.

This is both conceptually more correct, and it also matches what
mapToVisibleRectInAncestorSpace() already does. Having all machineries do this
at the same place in the tree is what fixes the editing-specific bug 596070.

As for layer clipping bug 527709, it just so happens that we specify the flow
thread as ancestor in mapLocalToAncestor(), which is invoked via
localToAncestorPoint() from PaintLayerClipper::calculateClipRects().
PaintLayerClipper does its work *before* fragments have been collected and set
up for a given layer, so it doesn't want mapLocalToAncestor() or anyone to
change to the visual coordinate space.

BUG=527709, 596070
R=leviw@chromium.org

Committed: https://crrev.com/8796ca1186b3ff3e3da105b3ee41f1698be01821
Cr-Commit-Position: refs/heads/master@{#382339}

[leviw_travelin_and_unemployed, 2016-03-21 17:18:48]

Beautiful. LGTM.

[leviw_travelin_and_unemployed, 2016-03-21 17:18:53]

The CQ bit was checked by leviw@chromium.org

[commit-bot: I haz the power, 2016-03-21 17:19:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1819603003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1819603003/20001

[commit-bot: I haz the power, 2016-03-21 18:43:27]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-03-21 18:44:22]

Description was changed from

==========
Shift flowthread-to-visual coordinate space conversion one level up in the tree.

The conversion now takes place between the flow thread and its parent multicol
container, rather than between the flow thread and its children.

This is both conceptually more correct, and it also matches what
mapToVisibleRectInAncestorSpace() already does. Having all machineries do this
at the same place in the tree is what fixes the editing-specific bug 596070.

As for layer clipping bug 527709, it just so happens that we specify the flow
thread as ancestor in mapLocalToAncestor(), which is invoked via
localToAncestorPoint() from PaintLayerClipper::calculateClipRects().
PaintLayerClipper does its work *before* fragments have been collected and set
up for a given layer, so it doesn't want mapLocalToAncestor() or anyone to
change to the visual coordinate space.

BUG=527709,596070
R=leviw@chromium.org
==========

to

==========
Shift flowthread-to-visual coordinate space conversion one level up in the tree.

The conversion now takes place between the flow thread and its parent multicol
container, rather than between the flow thread and its children.

This is both conceptually more correct, and it also matches what
mapToVisibleRectInAncestorSpace() already does. Having all machineries do this
at the same place in the tree is what fixes the editing-specific bug 596070.

As for layer clipping bug 527709, it just so happens that we specify the flow
thread as ancestor in mapLocalToAncestor(), which is invoked via
localToAncestorPoint() from PaintLayerClipper::calculateClipRects().
PaintLayerClipper does its work *before* fragments have been collected and set
up for a given layer, so it doesn't want mapLocalToAncestor() or anyone to
change to the visual coordinate space.

BUG=527709,596070
R=leviw@chromium.org

Committed: https://crrev.com/8796ca1186b3ff3e3da105b3ee41f1698be01821
Cr-Commit-Position: refs/heads/master@{#382339}
==========

[commit-bot: I haz the power, 2016-03-21 18:44:23]

Patchset 2 (id:??) landed as
https://crrev.com/8796ca1186b3ff3e3da105b3ee41f1698be01821
Cr-Commit-Position: refs/heads/master@{#382339}

[mstensho (USE GERRIT), 2016-04-18 18:41:14]

This also fixed bug 470978.