Merge 143356

Merge 143356
> Text Autosizing: prevent oscillation of font sizes during autosizing
> https://bugs.webkit.org/show_bug.cgi?id=108205
> 
> Patch by Tim Volodine <timvolodine@chromium.org>; on 2013-02-19
> Reviewed by Kenneth Rohde Christiansen.
> 
> Source/WebCore:
> 
> On some websites autosized font-sizes oscillate due to layouts caused by
> hovering or incremental page loading (and on other sites font sizes do
> eventually stabilize, but it takes many layouts before they reach a steady
> size). To prevent all these cases, we no longer allow the autosizing
> multiplier to change after it has been set (to a value other than 1).
> 
> This won't always give exactly the same results, but testing on 2000 top
> sites shows that this makes little difference in practice, and it prevents
> these very jarring cases. As a happy side-effect, this speeds up layouts
> as font sizes change less.
> 
> Test: fast/text-autosizing/oscillation-javascript-fontsize-change.html
> 
> * page/FrameView.cpp:
> (WebCore::FrameView::setFrameRect):
> * page/Settings.cpp:
> (WebCore::Settings::setTextAutosizingFontScaleFactor):
> * rendering/TextAutosizer.cpp:
> (WebCore::TextAutosizer::recalculateMultipliers):
> (WebCore):
> (WebCore::TextAutosizer::processContainer):
> * rendering/TextAutosizer.h:
> (TextAutosizer):
> 
> LayoutTests:
> 
> Added overflow-y:hidden to some existing tests, since previously those tests
> would start off with incorrect multipliers (because mainFrame->view()-layoutSize()
> is initially 785 instead of 800 as ScrollView wrongly guesses a scrollbar will
> be needed), and then the multipliers would get corrected on a subsequent layout.
> Now that we don't allow the multiplier to change after being set, it needs to be
> right first time.
> Also added specific oscillation test triggered by javascript.
> 
> * fast/text-autosizing/constrained-height-body-expected.html:
> * fast/text-autosizing/constrained-height-body.html:
> * fast/text-autosizing/constrained-then-float-ancestors-expected.html:
> * fast/text-autosizing/constrained-then-float-ancestors.html:
> * fast/text-autosizing/constrained-then-position-fixed-ancestors-expected.html:
> * fast/text-autosizing/constrained-then-position-fixed-ancestors.html:
> * fast/text-autosizing/nested-em-line-height-expected.html:
> * fast/text-autosizing/nested-em-line-height.html:
> * fast/text-autosizing/oscillation-javascript-fontsize-change-expected.html: Added.
> * fast/text-autosizing/oscillation-javascript-fontsize-change.html: Added.
> * fast/text-autosizing/simple-paragraph-expected.html:
> * fast/text-autosizing/simple-paragraph.html:
> * fast/text-autosizing/span-child-expected.html:
> * fast/text-autosizing/span-child.html:
> * fast/text-autosizing/unwrappable-blocks-expected.html:
> * fast/text-autosizing/unwrappable-blocks.html:
> * fast/text-autosizing/unwrappable-inlines-expected.html:
> * fast/text-autosizing/unwrappable-inlines.html:

TBR=commit-queue@webkit.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=143934

[Peter Beverloo, 2013-02-25 17:03:24]

Committed patchset #1 manually as r143934.