Support compiling libANGLE as a static or shared library.

BUG=angle:733

Change-Id: If27d3330534bce0f5b691010ea7d97bcb7579122
Reviewed-on: https://chromium-review.googlesource.com/231052
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
Clean up Adapter LUID queries.

We might need to revisit this when we implement other GL
back-ends.

BUG=angle:773

Change-Id: I6e742254bd0df8cc899ea02a523992b4d66dfd68
Reviewed-on: https://chromium-review.googlesource.com/229061
Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Fix override keyword in Renderer9.h.

BUG=angle:773

Change-Id: I1d69b79ed8f85a2e9238cee1ffada11ee362cffb
Reviewed-on: https://chromium-review.googlesource.com/232395
Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>