Remove uses of CACFContextRef and CARender* from WebCore

Remove uses of CACFContextRef and CARender* from WebCore

These types are now wrapped in a WKCACFContext type exported by
WebKitSystemInterface.

Fixes <http://webkit.org/b/43244>.

Reviewed by Sam Weinig.

WebCore:

* platform/graphics/win/WKCACFContextFlusher.cpp:
(WebCore::WKCACFContextFlusher::addContext):
(WebCore::WKCACFContextFlusher::removeContext):
(WebCore::WKCACFContextFlusher::flushAllContexts):
* platform/graphics/win/WKCACFContextFlusher.h:
Changed to use WKCACFContext. We don't retain/release the context when
putting it into/taking it out of the set. WKCACFContext is not a
ref-counted type, so we can't retain/release it, but the
retain/release was also unnecessary as WKCACFLayerRenderer calls
removeContext before the context is destroyed.

* platform/graphics/win/WKCACFLayer.cpp:
(WebCore::WKCACFLayer::becomeRootLayerForContext):
* platform/graphics/win/WKCACFLayer.h:
Changed to use WKCACFContext.

* platform/graphics/win/WKCACFLayerRenderer.cpp:
(WebCore::WKCACFLayerRenderer::didFlushContext):
(WebCore::WKCACFLayerRenderer::WKCACFLayerRenderer):
(WebCore::WKCACFLayerRenderer::~WKCACFLayerRenderer):
(WebCore::WKCACFLayerRenderer::layerTreeDidChange):
(WebCore::WKCACFLayerRenderer::createRenderer):
(WebCore::WKCACFLayerRenderer::destroyRenderer):
(WebCore::WKCACFLayerRenderer::render): Also replaced uses of
CGSRegion with WebKitSystemInterface functions/types.
(WebCore::WKCACFLayerRenderer::resetDevice):
* platform/graphics/win/WKCACFLayerRenderer.h:
Replaced our CACFContextRef, CARenderContext, and CARenderOGLContext
with a single WKCACFContext, which wraps all three. We hold a bare
pointer to it and destroy it in our destructor.

WebKitLibraries:

Add WKCACFContext and related functions

* win/lib/WebKitSystemInterface.lib:
* win/lib/WebKitSystemInterface_debug.lib:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@70129 268f45cc-cd09-0410-ab3c-d52691b4dbfc