Fix d3d9 copyToStorage dirty flag. This flag wasn't being set in the 2D version of this method. The bug would only cause a performance penalty on Windows XP machines. BUG=angle:729 Change-Id: I516206740becc90438d613ae9abb3ac550733aed Reviewed-on: https://chromium-review.googlesource.com/219860 Reviewed-by: Brandon Jones <bajones@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>