Reviewed by Dan Bernstein.

Add a simplified normal flow layout path optimization for overflow recomputation
and for positioned objects inside relative positioned containers.

Currently there is an optimized code path for positioned objects, but as soon as
we encounter a normal flow object in the containing block chain, we lose the
optimization.

This patch adds a new type of style difference called SimplifiedLayout that is
returned when only overflow needs to be recomputed. Whenever a transform changes,
this is the hint returned now instead of a full layout.
        
In addition, when positioned objects need layout and start marking up the
containing block chain, we now propagate the fact that the layout is simplified
all the way up to the root, even when we encounter normal flow containing
blocks.
        
The layoutOnlyPositionedObjects function has been renamed to simplifiedLayout()
and is now used for all of these cases (in addition to what it handled before).
        
The simplified layout optimization (even in ToT) did not work correctly when
static distances needed to be recomputed. In order to make static distance
computations work with simplified layout, positioned objects now always compute
their static offsets, even if they explicitly specify left/top.  That way normal
flow layout never has to re-run when the positioned object moves.  This makes
movement of a positioned object along a single non-auto axis much faster when the
other axis is auto. Because this code kicked in more often for absolutely positioned
objects whose original display was inline, I went ahead and fixed the trailing space
issue with those objects.  This causes a bunch of layout tests to progress.

Added fast/block/positioning/static-inline-position-dynamic.html and trailing-space-test.html.

* rendering/RenderBlock.cpp:
(WebCore::RenderBlock::layoutBlock):
(WebCore::RenderBlock::adjustPositionedBlock):
(WebCore::RenderBlock::simplifiedNormalFlowLayout):
(WebCore::RenderBlock::simplifiedLayout):
* rendering/RenderBlock.h:
* rendering/RenderBlockLineLayout.cpp:
(WebCore::setStaticPositions):
(WebCore::RenderBlock::findNextLineBreak):
* rendering/RenderBox.cpp:
(WebCore::RenderBox::styleDidChange):
(WebCore::RenderBox::positionLineBox):
* rendering/RenderBoxModelObject.cpp:
(WebCore::RenderBoxModelObject::styleWillChange):
* rendering/RenderFlexibleBox.cpp:
(WebCore::RenderFlexibleBox::layoutBlock):
(WebCore::RenderFlexibleBox::layoutHorizontalBox):
(WebCore::RenderFlexibleBox::layoutVerticalBox):
* rendering/RenderObject.cpp:
(WebCore::RenderObject::RenderObject):
(WebCore::RenderObject::adjustStyleDifference):
(WebCore::RenderObject::setStyle):
(WebCore::RenderObject::styleDidChange):
* rendering/RenderObject.h:
(WebCore::RenderObject::needsLayout):
(WebCore::RenderObject::needsPositionedMovementLayoutOnly):
(WebCore::RenderObject::needsSimplifiedNormalFlowLayout):
(WebCore::RenderObject::setNeedsLayout):
(WebCore::RenderObject::setChildNeedsLayout):
(WebCore::RenderObject::setNeedsSimplifiedNormalFlowLayout):
(WebCore::RenderObject::markContainingBlocksForLayout):
* rendering/RenderTable.cpp:
(WebCore::RenderTable::layout):
* rendering/style/RenderStyle.cpp:
(WebCore::RenderStyle::diff):
* rendering/style/RenderStyleConstants.h:
* rendering/svg/RenderSVGText.cpp:
(WebCore::RenderSVGText::layout):

LayoutTests: Add a simplified normal flow layout path optimization for overflow recomputation
and for positioned objects inside relative positioned containers.

Reviewed by Dan Bernstein.

Currently there is an optimized code path for positioned objects, but as soon as
we encounter a normal flow object in the containing block chain, we lose the
optimization.

This patch adds a new type of style difference called SimplifiedLayout that is
returned when only overflow needs to be recomputed. Whenever a transform changes,
this is the hint returned now instead of a full layout.
        
In addition, when positioned objects need layout and start marking up the
containing block chain, we now propagate the fact that the layout is simplified
all the way up to the root, even when we encounter normal flow containing
blocks.
        
The layoutOnlyPositionedObjects function has been renamed to simplifiedLayout()
and is now used for all of these cases (in addition to what it handled before).
        
The simplified layout optimization (even in ToT) did not work correctly when
static distances needed to be recomputed. In order to make static distance
computations work with simplified layout, positioned objects now always compute
their static offsets, even if they explicitly specify left/top.  That way normal
flow layout never has to re-run when the positioned object moves.  This makes
movement of a positioned object along a single non-auto axis much faster when the
other axis is auto. Because this code kicked in more often for absolutely positioned
objects whose original display was inline, I went ahead and fixed the trailing space
issue with those objects.  This causes a bunch of layout tests to progress.

Added fast/block/positioning/static-inline-position-dynamic.html and trailing-space-test.html.

* animations/dynamic-stylesheet-loading-expected.txt:
* animations/keyframe-timing-functions-expected.txt:
* fast/block/positioning/static-inline-position-dynamic.html: Added.
* fast/block/positioning/trailing-space-test.html: Added.
* fast/dynamic/ancestor-to-absolute-expected.txt:
* fast/forms/input-appearance-elementFromPoint-expected.txt:
* fast/forms/input-hit-test-border-expected.txt:
* platform/mac/fast/block/positioning/002-expected.png:
* platform/mac/fast/block/positioning/003-expected.png:
* platform/mac/fast/block/positioning/004-expected.png:
* platform/mac/fast/block/positioning/005-expected.png:
* platform/mac/fast/block/positioning/006-expected.png:
* platform/mac/fast/block/positioning/007-expected.png:
* platform/mac/fast/block/positioning/008-expected.png:
* platform/mac/fast/block/positioning/009-expected.png:
* platform/mac/fast/block/positioning/010-expected.png:
* platform/mac/fast/block/positioning/011-expected.png:
* platform/mac/fast/block/positioning/012-expected.png:
* platform/mac/fast/block/positioning/013-expected.png:
* platform/mac/fast/block/positioning/014-expected.png:
* platform/mac/fast/block/positioning/015-expected.png:
* platform/mac/fast/block/positioning/016-expected.png:
* platform/mac/fast/block/positioning/017-expected.png:
* platform/mac/fast/block/positioning/018-expected.png:
* platform/mac/fast/block/positioning/019-expected.png:
* platform/mac/fast/block/positioning/020-expected.png:
* platform/mac/fast/block/positioning/021-expected.png:
* platform/mac/fast/block/positioning/022-expected.png:
* platform/mac/fast/block/positioning/023-expected.png:
* platform/mac/fast/block/positioning/024-expected.png:
* platform/mac/fast/block/positioning/025-expected.png:
* platform/mac/fast/block/positioning/026-expected.png:
* platform/mac/fast/block/positioning/027-expected.png:
* platform/mac/fast/block/positioning/028-expected.png:
* platform/mac/fast/block/positioning/029-expected.png:
* platform/mac/fast/block/positioning/030-expected.png:
* platform/mac/fast/block/positioning/031-expected.png:
* platform/mac/fast/block/positioning/032-expected.png:
* platform/mac/fast/block/positioning/033-expected.png:
* platform/mac/fast/block/positioning/034-expected.png:
* platform/mac/fast/block/positioning/035-expected.png:
* platform/mac/fast/block/positioning/036-expected.png:
* platform/mac/fast/block/positioning/037-expected.png:
* platform/mac/fast/block/positioning/038-expected.png:
* platform/mac/fast/block/positioning/039-expected.png:
* platform/mac/fast/block/positioning/040-expected.png:
* platform/mac/fast/block/positioning/041-expected.png:
* platform/mac/fast/block/positioning/042-expected.png:
* platform/mac/fast/block/positioning/043-expected.png:
* platform/mac/fast/block/positioning/044-expected.png:
* platform/mac/fast/block/positioning/045-expected.png:
* platform/mac/fast/block/positioning/046-expected.png:
* platform/mac/fast/block/positioning/047-expected.checksum:
* platform/mac/fast/block/positioning/047-expected.png:
* platform/mac/fast/block/positioning/048-expected.png:
* platform/mac/fast/block/positioning/049-expected.png:
* platform/mac/fast/block/positioning/050-expected.png:
* platform/mac/fast/block/positioning/056-expected.txt:
* platform/mac/fast/block/positioning/061-expected.png:
* platform/mac/fast/block/positioning/062-expected.png:
* platform/mac/fast/block/positioning/auto/005-expected.txt:
* platform/mac/fast/block/positioning/auto/006-expected.txt:
* platform/mac/fast/block/positioning/auto/007-expected.png:
* platform/mac/fast/block/positioning/auto/vertical-lr/005-expected.txt:
* platform/mac/fast/block/positioning/auto/vertical-lr/006-expected.txt:
* platform/mac/fast/block/positioning/auto/vertical-lr/007-expected.checksum:
* platform/mac/fast/block/positioning/auto/vertical-lr/007-expected.png:
* platform/mac/fast/block/positioning/auto/vertical-rl/005-expected.txt:
* platform/mac/fast/block/positioning/auto/vertical-rl/006-expected.txt:
* platform/mac/fast/block/positioning/auto/vertical-rl/007-expected.checksum:
* platform/mac/fast/block/positioning/auto/vertical-rl/007-expected.png:
* platform/mac/fast/block/positioning/fixed-positioning-scrollbar-bug-expected.txt:
* platform/mac/fast/block/positioning/inline-block-relposition-expected.checksum:
* platform/mac/fast/block/positioning/inline-block-relposition-expected.png:
* platform/mac/fast/block/positioning/inline-block-relposition-expected.txt:
* platform/mac/fast/block/positioning/move-with-auto-width-expected.png:
* platform/mac/fast/block/positioning/negative-rel-position-expected.png:
* platform/mac/fast/block/positioning/relative-overconstrained-expected.png:
* platform/mac/fast/block/positioning/relative-overflow-block-expected.txt:
* platform/mac/fast/block/positioning/static-inline-position-dynamic-expected.checksum: Added.
* platform/mac/fast/block/positioning/static-inline-position-dynamic-expected.png: Added.
* platform/mac/fast/block/positioning/static-inline-position-dynamic-expected.txt: Added.
* platform/mac/fast/block/positioning/trailing-space-test-expected.checksum: Added.
* platform/mac/fast/block/positioning/trailing-space-test-expected.png: Added.
* platform/mac/fast/block/positioning/trailing-space-test-expected.txt: Added.
* platform/mac/fast/clip/001-expected.txt:
* platform/mac/fast/clip/004-expected.txt:
* platform/mac/fast/clip/006-expected.txt:
* platform/mac/fast/clip/007-expected.txt:
* platform/mac/fast/clip/008-expected.txt:
* platform/mac/fast/clip/009-expected.txt:
* platform/mac/fast/clip/010-expected.txt:
* platform/mac/fast/clip/011-expected.txt:
* platform/mac/fast/clip/012-expected.txt:
* platform/mac/fast/clip/013-expected.txt:
* platform/mac/fast/clip/014-expected.txt:
* platform/mac/fast/clip/nestedTransparencyClip-expected.txt:
* platform/mac/fast/clip/outline-overflowClip-expected.txt:
* platform/mac/fast/forms/input-appearance-preventDefault-expected.txt:
* platform/mac/fast/invalid/014-expected.txt:
* platform/mac/fast/layers/layer-visibility-expected.txt:
* platform/mac/fast/repaint/layout-state-scrolloffset-expected.txt:
* platform/mac/fast/repaint/layout-state-scrolloffset2-expected.txt:
* platform/mac/fast/repaint/layout-state-scrolloffset3-expected.txt:
* platform/mac/tables/mozilla/bugs/bug51140-expected.txt:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@81992 268f45cc-cd09-0410-ab3c-d52691b4dbfc