Chrome Version: 66.0.3334.0 (Official Build) dec7220f080ea5dc647603e2dd8092afe6bb302f-refs/heads/master@{#532207} (32/64-bit) 
OS: Win(7,8,8.1,10) and Mac(10.12.6, 10.13.1, 10.13.3).

What steps will reproduce the problem?
1. Launch Chrome, open DevTools, dock it to bottom and go to 'Application' section.
2. Press 'Tab' key from keyboard such that focus reaches to 'Read more about the web manifest' link.
3. Now press "Shift + F10" key from keyborad and observe.

Actual: Unable to open context menu using keyboard.
Expected: Should be able to open context menu using keyboard.

This is a regression issue, broken in M-64 series, below is manual regression range.

Good build: 64.0.3264.0 (Revision: 515410)
Bad build: 64.0.3265.0 (Revision: 515780)

Using the per-revision bisect providing the bisect results:

You are probably looking for a change made after 515748 (known good), but no later than 515750 (first known bad).
CHANGELOG URL:
The script might not always return single CL as suspect as some perf builds might get missing due to failure.
  https://chromium.googlesource.com/chromium/src/+log/d12f1ff7b61c6cc0f8e07a149fa6ef5a701c4882..2cd778f652fe1166f656da1392b1fb0db4bb31b6

Suspecting: https://chromium.googlesource.com/chromium/src/+/2cd778f652fe1166f656da1392b1fb0db4bb31b6

@einbinder : Could you please look into the issue, pardon me if it has nothing to do with your changes and if possible please assign it to concern owner.

NOTE:
1. Able to open context menu via keyboard when DevTools is docked to right/left.
2. This issue is not reproducible on Linux OS.
3. This issue is also reproducible on M-64 Stable/Beta (build # 64.0.3282.119) and M-65 Dev (build #65.0.3325.18).

Kindly review the attached 'Actual behavior' screen-cast for reference.

Thank you.
 

Deleted: Actual behavior.mp4 1.1 MB

	Actual behavior.mp4 1.1 MB View Download