Add support for the "first" value of the hanging-punctuation property.

Add support for the "first" value of the hanging-punctuation property.
https://bugs.webkit.org/show_bug.cgi?id=154919

Reviewed by Simon Fraser.

Source/WebCore:

New tests added in fast/text.

Implement the "first" value for hanging-punctuation as described here:
https://drafts.csswg.org/css-text-3/#propdef-hanging-punctuation

* rendering/RenderBlockFlow.cpp:
(WebCore::RenderBlockFlow::computeInlinePreferredLogicalWidths):
Update the preferred logical width computation to factor in hanging punctuation.
This check is similar to the text-indent logic in that we only want to do it for
the first formatted line.

* rendering/RenderBlockFlow.h:
(WebCore::RenderBlockFlow::simpleLineLayout):
Make sure to turn off simple line layout when hanging punctuation is present. Eventually
it should be feasible to support this in simple line layout, but since the full line
layout model has to work with it anyway, we are starting there.

* rendering/RenderBlockLineLayout.cpp:
(WebCore::inlineAncestorHasStartBorderPaddingOrMargin):
(WebCore::isLastInFlowRun):
Helper functions that are needed to determine whether or not we're allowed to apply
hanging punctuation "first" to a text run.

(WebCore::RenderBlockFlow::computeInlineDirectionPositionsForSegment):
This function manipulates logicalLeft and availableWidth when hanging punctuation
is present to shift the line as needed and to expand the availableWidth of the line.

* rendering/RenderText.cpp:
(WebCore::isHangablePunctuationAtLineStart):
(WebCore::isHangablePunctuationAtLineEnd):
(WebCore::RenderText::hangablePunctuationStartWidth):
(WebCore::RenderText::trimmedPrefWidths):
* rendering/RenderText.h:
RenderText has a helper function for handing back the hangable punctuation width. This
is used everywhere line layout wants to apply that offset. There are also helper functions
that detect whether the character is a hangable punctuation character.

* rendering/SimpleLineLayout.cpp:
(WebCore::SimpleLineLayout::canUseForWithReason):
(WebCore::SimpleLineLayout::printReason):
Turn off simple line layout when hanging punctuation is enabled.

* rendering/line/BreakingContext.h:
(WebCore::BreakingContext::handleText):
Modified to expand the available width when hanging punctuation is present so that we
know we have more room on the line.

* rendering/line/LineWidth.h:
(WebCore::LineWidth::isFirstLine):
Add an accessor for whether or not we're the first line.

LayoutTests:

* fast/text/hanging-punctuation-first-expected.html: Added.
* fast/text/hanging-punctuation-first-rtl-expected.html: Added.
* fast/text/hanging-punctuation-first-rtl.html: Added.
* fast/text/hanging-punctuation-first.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@197464 268f45cc-cd09-0410-ab3c-d52691b4dbfc