edward@ Thanks for the issue.

Tested this issue on Windows 10 and Mac OS 10.12.6 on the reported version 65.0.3325.181 and the latest Canary 67.0.3393.0 and unable to reproduce the issue.

On hitting Ctrl-H and typing p, u, t, z, y, cannot observe any Keystroke missing. Also tried the same in Bookmarks Manager page and no issues are observed.
Attached is the screen cast for reference.

Request you to retry the issue on a new chrome profile without any flags/extensions and update the thread with the observations.

Thanks..

Deleted: 830167.mp4 558 KB

	830167.mp4 558 KB View Download

I created a new profile and was still able to reproduce the problem. To make the repro more deterministic, I also reproduced it with a small AutoHotKey script that simulate a reasonably fast typist (5 characters per second, or 70 words per minute).

#T::
SetKeyDelay, 200
SendEvent ^h123456789
return

Steps to repro:
1. Install AutoHotKey from https://autohotkey.com/.
2. Save the above script (4 lines) to a text file ending in .ahk.
3. Double-click the file.
4. In a new profile in Chrome, open a new tab.
5. Press Windows+T.

Cook-kid substitute steps if you use scoop (http://scoop.sh/):
1. scoop install autohotkey
3. autohotkey thetestfile.ahk

Result:
The script will type Control+H,1,2,3,4,5,6,7,8,9. The history window, opens but only 3456789 appears in the search box.

Thank you for providing more feedback. Adding the requester to the cc list.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Able to reproduce the issue on reported chrome version 66.0.3359.139 and on latest chrome 68.0.3432.0 using Windows 10. 
 
Same behavior is seen on M60(60.0.3112.113) hence considering it as non-regression and marking it as Untriaged.

Note: This issue is specific to Windows only.

Thanks! 

***Mass UI Triage***

We are able to reproduce this bug on latest canary #72.0.3619.0.Hence adding respective labels for further triage. Thanks!