https://bugs.webkit.org/show_bug.cgi?id=68650

https://bugs.webkit.org/show_bug.cgi?id=68650

Make determineStartPosition smart enough to not skip over clean lines that have moved to a new
region with a different available content logical width. When this happens, we go ahead and treat
the line as dirty.

Reviewed by Sam Weinig.

Source/WebCore:

Covered by existing fast/regions tests.

* rendering/RenderBlock.cpp:
(WebCore::RenderBlock::layoutBlock):
Disable region fitting if we detect that the regions all have uniform widths. In this case we know
the content width can't vary, so there's no reason to waste time worrying about it.

(WebCore::RenderBlock::computeLogicalLocationForFloat):
Pull the content width checking code into computeLogicalLocationForFloat, since we've incorporated
region fitting into the fixed offsets now rather than the line functions.

(WebCore::RenderBlock::positionNewFloats):
Changed because more code moved from here into computeLogicalLocationForFloat.

(WebCore::RenderBlock::adjustForRegionFittingIfNeeded):
No changes. Just moved the function above the left offset function.

(WebCore::RenderBlock::logicalLeftOffsetForContent):
(WebCore::RenderBlock::logicalRightOffsetForContent):
Added. These new functions give the fixed left and right offsets for lines in a particular region.
When no regions are present or when all the regions have a uniform width, they are identical
to the versions of the functions that take no arguments.

(WebCore::RenderBlock::logicalRightOffsetForLine):
Changed to no longer do region fitting, since that's built into logicalRightOffsetForContent now.

(WebCore::RenderBlock::lineWidthForPaginatedLineChanged):
New function that takes a root line box and compares its cached old content width with the width
available at the line's new location.

* rendering/RenderBlock.h:
(WebCore::RenderBlock::logicalRightOffsetForLine):
(WebCore::RenderBlock::logicalLeftOffsetForLine):
Modified to call the logicalXXXOffsetForContent functions that take a block direction position.

(WebCore::RenderBlock::logicalRightOffsetForContent):
(WebCore::RenderBlock::logicalLeftOffsetForContent):
Added the new functions that take a position so that they can fit to the correct region.

(WebCore::RenderBlock::availableLogicalWidthForContent):
New helper function that calls right - left (similar to the corresponding line function that includes
floats).

* rendering/RenderBlockLineLayout.cpp:
(WebCore::RenderBlock::determineStartPosition):
Patched to check if a line has moved to a place with a different available content width. If so, the line
is dirtied so that line layout can re-run.

* rendering/RootInlineBox.cpp:
(WebCore::RootInlineBox::RootInlineBox):
(WebCore::RootInlineBox::alignBoxesInBlockDirection):
Sets the paginated line width from the current block logical height.

* rendering/RootInlineBox.h:
(WebCore::RootInlineBox::paginationStrut):
(WebCore::RootInlineBox::setPaginationStrut):
Fixed paginationStrut to be LayoutUnit instead of int.

(WebCore::RootInlineBox::paginatedLineWidth):
(WebCore::RootInlineBox::setPaginatedLineWidth):
Added paginatedLineWidth getter/setter for caching the content width for a given root line.

LayoutTests:

* platform/mac/fast/regions/webkit-flow-floats-inside-regions-bounds-expected.png:
* platform/mac/fast/regions/webkit-flow-floats-inside-regions-bounds-expected.txt:
* platform/mac/fast/regions/webkit-flow-inlines-inside-regions-bounds-expected.png:
* platform/mac/fast/regions/webkit-flow-inlines-inside-regions-bounds-expected.txt:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@95750 268f45cc-cd09-0410-ab3c-d52691b4dbfc