Move utility functions from WebLayer to PlatformCALayer
https://bugs.webkit.org/show_bug.cgi?id=133887
<rdar://problem/17309622>

Reviewed by Simon Fraser.

Move some utility functions from WebLayer.h/.mm to PlatformCALayer.
Provide ObjC implementation in PlatformCALayerMac. A future patch will
provide corresponding Windows versions.

* WebCore.exp.in:
* platform/graphics/ca/PlatformCALayer.cpp:
(WebCore::PlatformCALayer::drawRepaintIndicator):
* platform/graphics/ca/PlatformCALayer.h:
* platform/graphics/ca/TileController.cpp:
(WebCore::TileController::blankPixelCountForTiles):
* platform/graphics/ca/TileGrid.cpp:
(WebCore::TileGrid::platformCALayerPaintContents):
* platform/graphics/ca/mac/PlatformCALayerMac.mm:
(PlatformCALayer::collectRectsToPaint):
(PlatformCALayer::drawLayerContents):
(PlatformCALayer::frameForLayer):
* platform/graphics/mac/WebLayer.h:
* platform/graphics/mac/WebLayer.mm:
(-[WebLayer drawInContext:]):
(WebCore::collectRectsToPaint): Deleted.
(WebCore::drawLayerContents): Deleted.
(WebCore::drawRepaintIndicator): Deleted.
(WebCore::frameForLayer): Deleted.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@169960 268f45cc-cd09-0410-ab3c-d52691b4dbfc