On iOS, the depth buffer is not being cleared correctly in WebGLRenderingContext::clearIfComposited because it is always returning after the check for !m_context->layerComposited(). This moves where the layer is being marked as composited from the mac-specific GraphicsContext3D::prepareTexture to the mac and iOS specific display function, which calls drawInCGLContext through its [super display] call.
Created attachment 232263 [details]
Comment on attachment 232263 [details]
Clearing flags on attachment: 232263
Committed r169467: <http://trac.webkit.org/changeset/169467>
All reviewed patches have been landed. Closing bug.