Version: 51.0.2677.0 dev
OS: Ubuntu 12.04,14.04,windows

What steps will reproduce the problem?
(1) Launch chrome and go to chrome://tracing page
(2) Click on "?" button on top R.H.S for help section and observe for scroll bar

Expected: No unwanted scroll bar should be seen on navigating to help section.
Actual: Instead unwanted scroll bars are seen in help section

This is a regression issue broken in M50.

Good build: 50.0.2651.0 dev
Bad Build: 50.0.2652.0 dev

CHANGELOG URL:
  https://chromium.googlesource.com/chromium/src/+log/b8e85606324596ee7decb1ddb0edb5651398bafd..5e9d81f956cab1871be97e7f4d1b7fbe9d9fbf7f

Suspecting https://codereview.chromium.org/1701703002 in catapult-deps-roller

@petrcermak: Please help in re-assigning if it is not related to your change.