DescriptorArray::kDescriptorFoo was renamed to
DescriptorArray::kEntryFooIndex in https://codereview.chromium.org/2688573003

TBR=ishell@chromium.org
NOTRY=true

Review-Url: https://codereview.chromium.org/2687083003
Cr-Commit-Position: refs/heads/master@{#43076}