Reviewed by Darin Adler.

        - fix <rdar://problem/5760774> Replying to a Mail message that contains
          fixed width text can change the size of the text

        Covered by existing tests: editing/pasteboard/5027857.html
                                   editing/pasteboard/paste-pre-002.html

        * css/CSSComputedStyleDeclaration.cpp:
        (WebCore::CSSComputedStyleDeclaration::getFontSizeCSSValuePreferringKeyword):
        Added. If the font-size is keyword-based, returns the keyword value
        instead of the pixel size.
        (WebCore::CSSComputedStyleDeclaration::getPropertyCSSValue): If
        font-family is a generic family, return the generic family instead of
        the the internal string -webkit-[serif|sans-serif|cursive|fantasy
        |monospace].
        (WebCore::CSSComputedStyleDeclaration::copyInheritableProperties):
        For the font-size property, prefer a keyword value over a pixel size.
        * css/CSSComputedStyleDeclaration.h:
        * editing/ApplyStyleCommand.cpp:
        (WebCore::StyleChange::currentlyHasStyle): For the font-size property,
        call getFontSizeCSSValuePreferringKeyword().
        * platform/graphics/FontDescription.h:
        (WebCore::FontDescription::keywordSize): Changed the return type to
        unsigned.
        (WebCore::FontDescription::setKeywordSize): Changed the parameter type
        to unsigned.
        (WebCore::FontDescription::m_keywordSize): Changed the type of this
        4-bit field to unsigned, because it takes values as high as 8.

LayoutTests:

        Reviewed by Darin Adler.

        - updated results for <rdar://problem/5760774> Replying to a Mail
          message that contains fixed width text can change the size of the text

        * editing/execCommand/19089-expected.txt:
        * editing/execCommand/5770834-1-expected.txt:
        * platform/mac/editing/deleting/delete-br-011-expected.txt:
        * platform/mac/editing/deleting/delete-select-all-001-expected.txt:
        * platform/mac/editing/execCommand/remove-formatting-2-expected.txt:
        * platform/mac/editing/pasteboard/5027857-expected.checksum:
        * platform/mac/editing/pasteboard/5027857-expected.png:
        * platform/mac/editing/pasteboard/5027857-expected.txt:
        * platform/mac/editing/pasteboard/paste-pre-002-expected.checksum:
        * platform/mac/editing/pasteboard/paste-pre-002-expected.png:
        * platform/mac/editing/pasteboard/paste-pre-002-expected.txt:
        * platform/mac/editing/style/block-style-004-expected.txt:
        * platform/mac/editing/style/block-style-005-expected.txt:
        * platform/mac/editing/style/block-style-006-expected.txt:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@43243 268f45cc-cd09-0410-ab3c-d52691b4dbfc