[Dolphin] Make more members and arguments const.

Bug: 921444
Change-Id: I07e7fd9ebd368639badb599c41bcb5ed8900e25d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1614724
Commit-Queue: Charles . <charleszhao@chromium.org>
Reviewed-by: Charles . <charleszhao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660697}
3 files changed