GitLab

This CL adds a few more methods that cause name collisions when Blink
is rewritten to match Chromium style:
- dragOperation
- locationInBackingMap

BUG=582312
TBR=dcheng@chromium.org

Review-Url: https://codereview.chromium.org/2805133006
Cr-Commit-Position: refs/heads/master@{#463039}