Remove the requirement that a format must be texturable to be renderable. Previously, to determine if a texture format was renderable, the texturable and renderable fields had to be and-ed together. This caused issues for formats such as D24S8 which can be renderable but not texturable depending on available extensions. Made the renderable flag a complete check that may be different than the textureable flag and removed assumptions that a format is texturable if renderable from the code. GL_DEPTH24_STENCIL8 now checks for ANGLE_depth_textures for texturability and ANGLE_depth_textures or OES_packed_depth_stencil for renderability. BUG=angle:752 Change-Id: I6d197cee72cc249e5996fa395303bdf43d246a87 Reviewed-on: https://chromium-review.googlesource.com/219093 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>