Reviewed by Eric.

    Reviewed by Eric.

        - http://bugzilla.opendarwin.org/show_bug.cgi?id=8696
          another round of GraphicsContext improvements

        * WebCore.xcodeproj/project.pbxproj: Added GraphicsContextCG.cpp.
        * html/CanvasRenderingContext2D.cpp:
        (WebCore::CanvasRenderingContext2D::scale): Use new GraphicsContext function.
        (WebCore::CanvasRenderingContext2D::rotate): Ditto.
        (WebCore::CanvasRenderingContext2D::translate): Ditto.
        * kwq/KWQComboBox.mm: Added include (not sure if this is needed for this patch,
        but it's needed for one of my upcoming ones).

        * platform/GraphicsContext.h: Changed fillColor and setFillColor to use Color
        instead of RGBA32. Removed setColorFromFillColor and setColorFromPen. Added
        scale, rotate, and translate functions.
        * platform/GraphicsContext.cpp:
        (WebCore::GraphicsContext::setFillColor): Changed to use Color instead of RGBA32.
        (WebCore::GraphicsContext::fillColor): Ditto.

        * platform/GraphicsTypes.h: Moved HorizontalAlignment here.
        * platform/Widget.h: Removed HorizontalAlignment from here.

        * platform/cg/GraphicsContextCG.cpp: Added. Started as a copy of GraphicsContextMac.mm.
        (WebCore::GraphicsContext::drawRect): Rewrote to not rely on [NSGraphicsContext currentContext].
        (WebCore::GraphicsContext::drawLine): Ditto.
        (WebCore::GraphicsContext::drawEllipse): Ditto.
        (WebCore::GraphicsContext::drawArc): Ditto.
        (WebCore::GraphicsContext::drawConvexPolygon): Ditto.
        (WebCore::GraphicsContext::fillRect): Ditto.
        (WebCore::GraphicsContext::setLineWidth):  Added check of paintingDisabled().
        (WebCore::GraphicsContext::setMiterLimit): Ditto.
        (WebCore::GraphicsContext::setAlpha): Ditto.
        (WebCore::GraphicsContext::clearRect): Ditto.
        (WebCore::GraphicsContext::strokeRect): Ditto.
        (WebCore::GraphicsContext::setLineCap): Ditto.
        (WebCore::GraphicsContext::setLineJoin): Ditto.
        (WebCore::GraphicsContext::clip): Ditto.
        (WebCore::GraphicsContext::scale): Added.
        (WebCore::GraphicsContext::rotate): Added.
        (WebCore::GraphicsContext::translate): Added.

        * platform/mac/GraphicsContextMac.mm: Moved most of this file into GraphicsContextCG.cpp.
        (WebCore::GraphicsContext::setCompositeOperation): Added check of paintingDisabled().

        * platform/mac/WebCoreSystemInterface.h: Added declarations so this header
        stands alone.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@14174 268f45cc-cd09-0410-ab3c-d52691b4dbfc