[CSS Regions] Assertion failure in some cases with inline blocks
https://bugs.webkit.org/show_bug.cgi?id=132859
Reviewed by Mihnea Ovidenie.
Source/WebCore:
The patch hardens the conditions when the region range caches are
populated to avoid desynchronizations when objects move during layout.
This is true especially in the case of the boxes found inside
inline blocks, that get their range from the containing line.
There is a new function |computedRegionRangeForBox| that will always
return a region range for a box using a best effort algorithm. This should
be used only when there's no need to cache region information.
This change also allows better control over the lifecycle of the
|RenderBoxRegionInfo| objects stored on the regions. We can now iterate
over the full range of the box when cleaning up the region box info. The
same applies for the width change detection function.
Test: fast/regions/inline-block-shifted-region.html
* rendering/RenderBlockLineLayout.cpp:
(WebCore::RenderBlockFlow::updateRegionForLine): Don't set the containing
region if the block doesn't have a range. The returned value would not
be correctly clamped.
* rendering/RenderBox.cpp:
(WebCore::RenderBlock::hasRegionRangeInFlowThread):
* rendering/RenderBox.h:
* rendering/RenderFlowThread.cpp:
(WebCore::RenderFlowThread::removeRenderBoxRegionInfo): Iterate only over
the range of the box, not from the start of the region chain.
(WebCore::RenderFlowThread::logicalWidthChangedInRegionsForBlock): Same as
above.
(WebCore::RenderFlowThread::hasCachedRegionRangeForBox):
(WebCore::RenderFlowThread::getRegionRangeForBoxFromCachedInfo):
(WebCore::RenderFlowThread::getRegionRangeForBox):
(WebCore::RenderFlowThread::computedRegionRangeForBox): Best effort function
to determine the range of a box. It will always return something as long
as the flow thread has regions.
(WebCore::RenderFlowThread::objectShouldFragmentInFlowRegion): Use the new function
to determine the range.
* rendering/RenderFlowThread.h:
* rendering/RenderNamedFlowThread.cpp:
(WebCore::RenderNamedFlowThread::absoluteQuadsForBox): Use the new function to determine
the range.
LayoutTests:
Test that moving lines with inline blocks doesn't cause an assertion.
* fast/regions/inline-block-shifted-region-expected.txt: Added.
* fast/regions/inline-block-shifted-region.html: Added.
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@168791 268f45cc-cd09-0410-ab3c-d52691b4dbfc
10 files changed
