[chromium] Remove unused transitional #defines from Platform API https://bugs.webkit.org/show_bug.cgi?id=105971 Patch by James Robinson <jamesr@chromium.org> on 2013-01-02 Reviewed by Adrienne Walker. These are leftovers from multi-sided patches that landed months ago. * chromium/public/WebContentLayerClient.h: (WebContentLayerClient): * chromium/public/WebLayer.h: * chromium/public/WebLayerTreeView.h: * chromium/public/WebThread.h: git-svn-id: https://svn.webkit.org/repository/webkit/trunk/Source/Platform/chromium/public@138687 268f45cc-cd09-0410-ab3c-d52691b4dbfc