Revert r154384 and r154674 as they broke selection rect computations for text with...

Revert r154384 and r154674 as they broke selection rect computations for text with ligatures.

Source/WebCore:

* platform/graphics/Font.cpp:
(WebCore::Font::drawText):
(WebCore::Font::drawEmphasisMarks):
(WebCore::Font::selectionRectForText):
(WebCore::Font::offsetForPosition):
* platform/graphics/FontFastPath.cpp:
(WebCore::Font::getGlyphsAndAdvancesForSimpleText):
(WebCore::Font::selectionRectForSimpleText):
(WebCore::Font::offsetForPositionForSimpleText):
* platform/graphics/GlyphBuffer.h:
* platform/graphics/WidthIterator.cpp:
(WebCore::WidthIterator::WidthIterator):
(WebCore::WidthIterator::advanceInternal):
(WebCore::WidthIterator::advanceOneCharacter):
* platform/graphics/WidthIterator.h:

LayoutTests:

* fast/text/partial-textruns-expected.html: Removed.
* fast/text/partial-textruns.html: Removed.
* fast/text/resources/PTS55F-webfont.ttf: Removed.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@163655 268f45cc-cd09-0410-ab3c-d52691b4dbfc