This cache is updated in the following locations:

1. GLES1: clientActiveTexture.
2. GLES1: disableClientState/enableClientState.
3. Context: linkProgram/useProgram/programBinary.
4. Context: bindVertexArray.
5. Vertex Array: most state changes.

Improves performance by about 6% in the GL no-op test. Also includes
fixes for keeping the client memory attribs mask in sync. The cache
also includes a boolean if there are any enabled client attributes.

Bug: angleproject:1391
Change-Id: I93b6a2c8492355958fd5483f14b70535729091d6
Reviewed-on: https://chromium-review.googlesource.com/1147437
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>