REGRESSION: -webkit-box-reflect does not show on video elements
https://bugs.webkit.org/show_bug.cgi?id=112397

Reviewed by Simon Fraser.

Source/WebCore:

Test: compositing/video/video-reflection.html

Support cloning specific CALayer subtypes in PlatformCALayer,
which allows reflections to work correctly for those layer types.
Specifically, add support for cloning AVPlayerLayer layers.

* platform/graphics/ca/GraphicsLayerCA.cpp:
(WebCore::GraphicsLayerCA::cloneLayer): Moved most of the
    implementation to PlatformCALayer::clone().
* platform/graphics/ca/PlatformCALayer.h:
* platform/graphics/ca/mac/PlatformCALayerMac.mm:
(PlatformCALayer::PlatformCALayer): Set the layerType to
    LayerTypeAVPlayerLayer if the PlatformLayer parameter is an
    AVPlayerLayer.
(PlatformCALayer::clone): Moved from GraphicsLayerCA::cloneLayer().
    Copy the player value to the new layer, if the current layer is
    a LayerTypeAVPlayerLayer.
(PlatformCALayer::playerLayer):
* platform/graphics/ca/win/PlatformCALayerWin.cpp:
(PlatformCALayer::clone): Moved from GraphicsLayerCA::cloneLayer().
    May want to add support for AVCFPlayerLayers in the future.

LayoutTests:

* compositing/video/video-reflection-expected.png: Added.
* compositing/video/video-reflection-expected.txt: Added.
* compositing/video/video-reflection.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@145915 268f45cc-cd09-0410-ab3c-d52691b4dbfc