Clean up some CSS & Font code

Clean up some CSS & Font code
https://bugs.webkit.org/show_bug.cgi?id=150767

Reviewed by Darin Adler.

This patch migrates some CSS code to use references instead of pointers.
It also migrates some Font code to use RefPtr instead of PassRefPtr.

No new tests because there is no behavior change.

* css/CSSDefaultStyleSheets.cpp:
(WebCore::CSSDefaultStyleSheets::loadFullDefaultStyle):
(WebCore::CSSDefaultStyleSheets::loadSimpleDefaultStyle):
(WebCore::CSSDefaultStyleSheets::ensureDefaultStyleSheetsForElement):
* css/CSSFontSelector.cpp:
(WebCore::createFontFace):
(WebCore::CSSFontSelector::addFontFaceRule):
* css/CSSFontSelector.h:
* css/DocumentRuleSets.cpp:
(WebCore::DocumentRuleSets::initUserStyle):
(WebCore::DocumentRuleSets::collectRulesFromUserStyleSheets):
(WebCore::DocumentRuleSets::appendAuthorStyleSheets):
* css/RuleSet.cpp:
(WebCore::RuleSet::addChildRules):
(WebCore::RuleSet::addRulesFromSheet):
* css/RuleSet.h:
* css/StyleInvalidationAnalysis.cpp:
(WebCore::StyleInvalidationAnalysis::StyleInvalidationAnalysis):
* platform/graphics/Font.cpp:
(WebCore::Font::verticalRightOrientationFont):
(WebCore::Font::uprightOrientationFont):
(WebCore::Font::smallCapsFont):
(WebCore::Font::emphasisMarkFont):
(WebCore::Font::brokenIdeographFont):
(WebCore::Font::nonSyntheticItalicFont):
(WebCore::Font::createScaledFont):
* platform/graphics/Font.h:
(WebCore::Font::variantFont):
* platform/graphics/cocoa/FontCocoa.mm:
(WebCore::Font::platformCreateScaledFont):
* svg/SVGFontFaceElement.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@191871 268f45cc-cd09-0410-ab3c-d52691b4dbfc