[chromium] Forward declare WebGraphicsContext3D in WebLayerTreeViewClient.h https://bugs.webkit.org/show_bug.cgi?id=100717 Patch by James Robinson <jamesr@chromium.org> on 2012-10-30 Reviewed by Adrienne Walker. Currently it isn't possible to include WebLayerTreeViewClient by itself. * chromium/public/WebLayerTreeViewClient.h: (WebKit): git-svn-id: https://svn.webkit.org/repository/webkit/trunk/Source/Platform/chromium/public@132938 268f45cc-cd09-0410-ab3c-d52691b4dbfc