Use underlying property set to refcount PropertySetCSSStyleDeclaration

Use underlying property set to refcount PropertySetCSSStyleDeclaration
https://bugs.webkit.org/show_bug.cgi?id=78257

Reviewed by Andreas Kling.

Clean up the PropertySetCSSStyleDeclaration refcounting. PropertySetCSSStyleDeclaration now
forwards the ref/deref to the underlying StylePropertySet.

Also made CSSComputedStyleDeclaration construction use the standard create() pattern.

* css/CSSComputedStyleDeclaration.cpp:
(WebCore::CSSComputedStyleDeclaration::ref):
(WebCore):
(WebCore::CSSComputedStyleDeclaration::deref):
* css/CSSComputedStyleDeclaration.h:
(WebCore::CSSComputedStyleDeclaration::create):
(CSSComputedStyleDeclaration):
(WebCore):
* css/CSSStyleDeclaration.h:
(CSSStyleDeclaration):
* css/StylePropertySet.cpp:
(WebCore::PropertySetCSSStyleDeclaration::PropertySetCSSStyleDeclaration):
(WebCore):
(WebCore::StylePropertySet::~StylePropertySet):
(WebCore::StylePropertySet::ensureCSSStyleDeclaration):
(WebCore::PropertySetCSSStyleDeclaration::makeMutable):
* css/StylePropertySet.h:
* editing/ApplyStyleCommand.cpp:
(WebCore::ApplyStyleCommand::splitAncestorsWithUnicodeBidi):
(WebCore::ApplyStyleCommand::removeEmbeddingUpToEnclosingBlock):
(WebCore::highestEmbeddingAncestor):
(WebCore::ApplyStyleCommand::computedFontSize):
* editing/EditingStyle.cpp:
(WebCore::EditingStyle::init):
(WebCore::EditingStyle::removeStyleAddedByNode):
(WebCore::EditingStyle::removeStyleConflictingWithStyleOfNode):
(WebCore::EditingStyle::triStateOfStyle):
(WebCore::EditingStyle::styleIsPresentInComputedStyleOfNode):
(WebCore::EditingStyle::mergeStyleFromRulesForSerialization):
(WebCore::backgroundColorInEffect):
* editing/Editor.cpp:
(WebCore::Editor::textDirectionForSelection):
* inspector/InspectorCSSAgent.cpp:
(WebCore::InspectorCSSAgent::getComputedStyleForNode):
* page/DOMWindow.cpp:
(WebCore::DOMWindow::getComputedStyle):
* svg/SVGAnimateElement.cpp:
(WebCore::getPropertyValue):
* svg/animation/SMILTimeContainer.cpp:
(WebCore::SMILTimeContainer::baseValueFor):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@107407 268f45cc-cd09-0410-ab3c-d52691b4dbfc