This method was removed in a prior patch.

BUG=angleproject:1898

Change-Id: I2ab3c36bbef4ce6c978cd4c09cc191c4e7ff7991
Reviewed-on: https://chromium-review.googlesource.com/677547Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>