Add marginBeforeIfFloating() to LayoutBlockFlow.

Add marginBeforeIfFloating() to LayoutBlockFlow.

Floats' margins need special attention for pagination, because they are not to
be eaten by page or column boundaries.

Clamp strut to >= 0 in LayoutBlockFlow::setPaginationStrutPropagatedFromChild()
instead of doing it (poorly) in calculateStrutForPropagation().

Removed calculateStrutForPropagation(), because there was hardly anything left
there now (and this lets us make marginBeforeIfFloating() private). This
function also turned out not to be universally usable, since we were already
calculating the strut on our own in adjustLinePositionForPagination() in one
case.

R=leviw@chromium.org

Committed: https://crrev.com/d27423b8964575c526a9eec2e4c672f9d2036245
Cr-Commit-Position: refs/heads/master@{#361084}

[leviw_travelin_and_unemployed, 2015-11-20 21:08:26]

LGTM with one point of personal preference. Thanks! :)

https://codereview.chromium.org/1460203003/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp (right):

https://codereview.chromium.org/1460203003/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp:2926: if (strut <
LayoutUnit())
I like the std::max approach a little moar, but that's just me.

https://codereview.chromium.org/1460203003/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp:2926: if (strut <
LayoutUnit())
I like the std::max approach a little moar, but that's just me.

[mstensho (USE GERRIT), 2015-11-23 08:59:56]

The CQ bit was checked by mstensho@opera.com

[mstensho (USE GERRIT), 2015-11-23 08:59:57]

The patchset sent to the CQ was uploaded after l-g-t-m from leviw@chromium.org
Link to the patchset: https://codereview.chromium.org/1460203003/#ps20001
(title: "code review")

[mstensho (USE GERRIT), 2015-11-23 09:00:02]

https://codereview.chromium.org/1460203003/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp (right):

https://codereview.chromium.org/1460203003/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp:2926: if (strut <
LayoutUnit())
On 2015/11/20 21:08:26, leviw wrote:
> I like the std::max approach a little moar, but that's just me.

Done.

https://codereview.chromium.org/1460203003/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp:2926: if (strut <
LayoutUnit())
On 2015/11/20 21:08:26, leviw wrote:
> I like the std::max approach a little moar, but that's just me.

Acknowledged.

[commit-bot: I haz the power, 2015-11-23 09:00:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1460203003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1460203003/20001

[commit-bot: I haz the power, 2015-11-23 10:29:48]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-11-23 10:30:32]

Patchset 2 (id:??) landed as
https://crrev.com/d27423b8964575c526a9eec2e4c672f9d2036245
Cr-Commit-Position: refs/heads/master@{#361084}