CSSValue: Clean up initial value construction.

CSSValue: Clean up initial value construction.
<http://webkit.org/b/72502>

Patch by Andreas Kling <kling@webkit.org> on 2011-11-16
Reviewed by Antti Koivisto.

Instead of determining whether a given CSSInitialValue is 'implicit' or not by
querying the CSSValue::ClassType (InitialClass vs. ImplicitInitialClass),
add a protected CSSValue member and set it from the CSSInitialValue constructor.

Also get rid of the CSSValue::m_isInitial bit since we can now replace the
checks by classType() == InitialClass.

No new tests, this is a cleanup.

* css/CSSInitialValue.h:
(WebCore::CSSInitialValue::CSSInitialValue):

    Poke 'implicit' constructor argument into CSSValue::m_isImplicit.

* css/CSSValue.cpp:
(WebCore::CSSValue::cssText):
(WebCore::CSSValue::destroy):

    Remove ImplicitInitialClass cases.

* css/CSSValue.h:
(WebCore::CSSValue::isImplicitInitialValue):
(WebCore::CSSValue::isInitialValue):
(WebCore::CSSValue::CSSValue):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@100449 268f45cc-cd09-0410-ab3c-d52691b4dbfc