FrameCapture: Capture GLES1 vertex buffer pointers. CaptureVertexPointerGLES1 was expecting only client-side vertex arrays and not checking whether a vertex buffer was bound. This patch fixes offsets in vertex buffers for GLES1, which can be seen in apps like Dr. Driving. The mClientVertexArrayMap index is now retrieved by entrypoint name, as the arrayClientPointerIndex is unset in the vertex buffer case. Bug: angleproject:5751 Change-Id: If40cae56bcdbed57885e83c49291cb000a884b0e Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2859826 Reviewed-by: Cody Northrop <cnorthrop@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Cody Northrop <cnorthrop@google.com>