StateManager11: Defer RenderTarget invalidation to draw. Although this adds a boolean check (and state flag maintenance) cost to each draw call, it makes ANGLE's internal life a lot simpler because it doesn't have to process a framebuffer change until the draw call. It turns out there are a few dependent checks of the Framebuffer that aren't always easy to do. In one test, Context destruction was triggering RenderTarget invalidation, after the Context had already freed the Framebuffer manager. This also fixes the problem in feature level 9_3 with framebuffer invalidation affecting the internal dirty bit set. (Note that it still dirties the Framebuffer for the next frame). BUG=chromium:767279 BUG=angleproject:2151 Change-Id: I74d61bddf9926004a04f712a9f9eb1205d5df0e1 Reviewed-on: https://chromium-review.googlesource.com/676657 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>