[chromium] Delete WebCompositor.h https://bugs.webkit.org/show_bug.cgi?id=101137 Reviewed by James Robinson. The implementation of this class is getting deleted and all WebKit-side users are already going via WebCompositorSupport instead. Source/Platform: * Platform.gypi: * chromium/public/WebCompositor.h: Removed. Source/WebKit/chromium: * tests/WebCompositorInputHandlerImplTest.cpp: git-svn-id: https://svn.webkit.org/repository/webkit/trunk/Source/Platform/chromium/public@134289 268f45cc-cd09-0410-ab3c-d52691b4dbfc