l_entered file shows what happens after letter 'l' is entered. You can see there're two previous entries for the text box.

mouse_on file shows what happens when the cursor is brought onto the first entry.

after_click shows what happens after that entry is clicked on. Note that the entry was NOT copied into the text box.

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Tested on latest Chrome Stable #62.0.3202.62, Canary #64.0.3247.0 on Windows 10, Mac 10.12.6 and Ubuntu 14.04 and able to reproduce the issue on latest Canary.

Using the per-revision bisect providing the bisect results,
Good build: 64.0.3244.0 (509944)
Bad build: 64.0.3245.0 (510270)

You are probably looking for a change made after 509960 (known good), but no later than 509961 (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/+/962a26fe7d0355903d4c2721faddcbe51e0ee45c

From the CL above, assigning the issue to the owner concerned.

@sebsg:  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 owner concerned.

Review-URL: https://chromium-review.googlesource.com/702056

Note: Issue is not reproduced on latest Stable #62.0.3202.62.

BTW, just noticed, that if don't input anything in text box but just click inside and then select an entry, the entry is selected as expected.
So the bug manifests itself when a partial text is input in the text box.

I have a fix ready, sending it in for review.

 Issue 779373  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/018bf76b5eb54811482aff02d07c14f4e1ce3c36

commit 018bf76b5eb54811482aff02d07c14f4e1ce3c36
Author: sebsg <sebsg@chromium.org>
Date: Mon Oct 30 18:45:57 2017

[Autofill] Fill Autocomplete correctly after suggestion.

Tbr-ing tkent@ for the TODO comment I added in WebInputElement.h

Bug:  777097 
Change-Id: Ia7c9b839521211d4527f067f848cd7988a49f64c
Tbr: tkent@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/734104
Commit-Queue: Sebastien Seguin-Gagnon <sebsg@chromium.org>
Reviewed-by: Roger McFarlane <rogerm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512553}
[modify] https://crrev.com/018bf76b5eb54811482aff02d07c14f4e1ce3c36/components/autofill/content/renderer/autofill_agent.cc
[modify] https://crrev.com/018bf76b5eb54811482aff02d07c14f4e1ce3c36/third_party/WebKit/public/web/WebInputElement.h

Tested the issue on Windows 10, Mac 10.12.6 and Ubuntu 14.04 using Chrome Canary version M64 - 64.0.3254.0 as per the issue mentioned in original comment. Observed that issue is working as intended (After typing some text in a text box and selecting the text from suggestions, then the complete text is populated in the text box). Hence adding TE-Verified labels. Attached the screencast for reference.

Thank you!

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	777097.mp4 3.0 MB View Download

 Issue 781091  has been merged into this issue.