Refactor application of additional style attributes for table elements.

Refactor application of additional style attributes for table elements.
<http://webkit.org/b/77095>

Reviewed by Darin Adler.

The primary purpose of this change is to reduce usage of CSSMappedAttributeDeclaration.
Instead of using the mapped attribute decl table for additional table style, just use
regular CSSMutableStyleDeclarations. We cache them all globally, except for the style
that's shared between a table's cells. That one is cached per-table since it depends
on the table's border and padding.

* dom/CSSMappedAttributeDeclaration.cpp:
(WebCore::CSSMappedAttributeDeclaration::~CSSMappedAttributeDeclaration):
* dom/MappedAttributeEntry.h:

    Remove the concept of persistent CSSMappedAttributeDeclarations. The hunk in
    ~CSSMappedAttributeDeclaration was wildly wrong since it would leave stale pointers
    in the decl table, but unreachable since we always leaked one ref to those decls.

* dom/StyledElement.h:
(WebCore::StyledElement::additionalAttributeStyle):
* html/HTMLTableCellElement.cpp:
(WebCore::HTMLTableCellElement::additionalAttributeStyle):
* html/HTMLTableCellElement.h:
(HTMLTableCellElement):
* html/HTMLTableColElement.cpp:
(WebCore::HTMLTableColElement::additionalAttributeStyle):
* html/HTMLTableColElement.h:
(HTMLTableColElement):
* html/HTMLTableElement.cpp:
(WebCore::HTMLTableElement::parseMappedAttribute):
(WebCore::leakBorderStyle):
(WebCore::HTMLTableElement::additionalAttributeStyle):
(WebCore::HTMLTableElement::createSharedCellStyle):
(WebCore::HTMLTableElement::additionalCellStyle):
(WebCore::leakGroupBorderStyle):
(WebCore::HTMLTableElement::additionalGroupStyle):
* html/HTMLTableElement.h:
(HTMLTableElement):
* html/HTMLTableSectionElement.cpp:
(WebCore::HTMLTableSectionElement::additionalAttributeStyle):
* html/HTMLTableSectionElement.h:
(HTMLTableSectionElement):

    Instead of collecting additional style decls into a vector, switch over to a
    "PassRefPtr<CSSMutableStyleDeclaration> additionalAttributeStyle()".
    All style declarations that can be reused for all elements are cached at the return
    sites, leaving only the shared table cell style which we cache on HTMLTableElement.
    Also removed the canHaveAdditionalAttributeStyleDecls() virtual since the default
    additionalAttributeStyle() will just return 0.

* css/CSSStyleSelector.cpp:
(WebCore::CSSStyleSelector::matchAllRules):

    Updated for the new additional style conventions.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@106015 268f45cc-cd09-0410-ab3c-d52691b4dbfc