Source/WebCore: <rdar://problem/10786000> Selection highlights of lines in adjoining blocks can overlap
https://bugs.webkit.org/show_bug.cgi?id=84489

Reviewed by Anders Carlsson.

Test: fast/block/line-layout/selection-highlight-overlap.html

* rendering/EllipsisBox.cpp:
(WebCore::EllipsisBox::selectionRect): Changed to use
selection{Top,Height}AdjustedForPrecedingBlock().
* rendering/InlineTextBox.cpp:
(WebCore::InlineTextBox::paintSelection): Ditto.
* rendering/RenderBlock.cpp:
(WebCore::RenderBlock::inlineSelectionGaps): Ditto.
(WebCore::RenderBlock::blockBeforeWithinSelectionRoot): Added. Returns the block which is
likely to contain the selected line just before the first line in this block, if it is
within the same selection root.
* rendering/RenderBlock.h:
* rendering/RootInlineBox.cpp:
(WebCore::RootInlineBox::selectionTopAdjustedForPrecedingBlock): Added. If the selection
starts before our block, finds the last line in the preceding block and adjusts the selection
top to avoid overlap with that line’s selection bottom.
* rendering/RootInlineBox.h:
(WebCore::RootInlineBox::selectionHeightAdjustedForPrecedingBlock): Added. Like
selectionHeight(), but uses selectionTopAdjustedForPrecedingBlock().

LayoutTests: Selection highlights of lines in adjoining blocks can overlap
https://bugs.webkit.org/show_bug.cgi?id=84489

Reviewed by Anders Carlsson.

* fast/block/line-layout/selection-highlight-overlap-expected.html: Added.
* fast/block/line-layout/selection-highlight-overlap.html: Added.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@114784 268f45cc-cd09-0410-ab3c-d52691b4dbfc