Use underlining metrics from the font file

Use underlining metrics from the font file
https://bugs.webkit.org/show_bug.cgi?id=138762

Patch by Myles C. Maxfield <litherum@gmail.com> on 2014-11-18
Reviewed by Dave Hyatt.

Source/WebCore:

Test: platform/mac/fast/css3-text/css3-text-decoration/text-decoration-thickness.html

* platform/graphics/FontMetrics.h: Adding variables for text decoration thickness and
underline position.
(WebCore::FontMetrics::FontMetrics):
(WebCore::FontMetrics::decorationThickness):
(WebCore::FontMetrics::setDecorationThickness):
(WebCore::FontMetrics::underlinePosition):
(WebCore::FontMetrics::setUnderlinePosition):
* platform/graphics/freetype/SimpleFontDataFreeType.cpp:
(WebCore::SimpleFontData::platformInit): Initialize new FontMetrics members.
* platform/graphics/ios/SimpleFontDataIOS.mm:
(WebCore::SimpleFontData::platformInit): Ditto.
* platform/graphics/mac/SimpleFontDataMac.mm:
(WebCore::SimpleFontData::platformInit): Ditto.
* platform/graphics/win/SimpleFontDataCGWin.cpp:
(WebCore::SimpleFontData::platformInit): Ditto.
* platform/graphics/win/SimpleFontDataCairoWin.cpp:
(WebCore::SimpleFontData::platformInit): Ditto.
* platform/graphics/win/SimpleFontDataWin.cpp:
(WebCore::SimpleFontData::initGDIFont): Ditto.
* rendering/InlineTextBox.cpp:
(WebCore::InlineTextBox::paintDecoration): Use FontMetrics data.
* style/InlineTextBoxStyle.cpp:
(WebCore::computeUnderlineOffset): Ditto.
(WebCore::visualOverflowForDecorations): Ditto.
* style/InlineTextBoxStyle.h:
(WebCore::textDecorationStrokeThickness): Deleted.
* svg/SVGFontData.cpp:
(WebCore::SVGFontData::initializeFontData): Initialize new FontMetrics members.

LayoutTests:

This patch makes underline placement platform-dependent.

* platform/mac/fast/css3-text/css3-text-decoration/text-decoration-thickness-expected.html: Renamed from LayoutTests/fast/css3-text/css3-text-decoration/text-decoration-thickness-expected.html.
* platform/mac/fast/css3-text/css3-text-decoration/text-decoration-thickness.html: Renamed from LayoutTests/fast/css3-text/css3-text-decoration/text-decoration-thickness.html.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@176263 268f45cc-cd09-0410-ab3c-d52691b4dbfc