This bug is not specific to the NTP and is not new in M58 either. I reproduced in M57 on some random web page.

It just looks like the end of the ripple animation of the tap on the tab switcher icon. When you tap on the tab itself rather than on the tab switched button to exit the overview, there is no highlight for example.

Anyway, looking.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e66cb66e93428dcd00ff059cc27d165b9361ba92

commit e66cb66e93428dcd00ff059cc27d165b9361ba92
Author: dgn <dgn@chromium.org>
Date: Tue Mar 07 17:45:20 2017

[Android] Fix flashing ripple on tab switch toolbar button

The ripple was initiated while in the tab switcher but invisible
because it's too dark, and is only visible for a short moment when
the tab is selected. This makes the ripple invisible while inside
the tab switcher.

BUG= 697455 

Review-Url: https://codereview.chromium.org/2734203002
Cr-Commit-Position: refs/heads/master@{#455121}

[modify] https://crrev.com/e66cb66e93428dcd00ff059cc27d165b9361ba92/chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarPhone.java

Fix is fairly simple, bug has been there for ages but is easy to reproduce and user visible, so requesting M58 merge.

Your change meets the bar and is auto-approved for M58. Please go ahead and merge the CL to branch 3029 manually. Please contact milestone owner if you have questions.
Owners: amineer@(clank), cmasso@(bling), bhthompson@(cros), govind@(desktop)

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

This issue has been approved for a merge. Please merge the fix to any appropriate branches as soon as possible!

If all merges have been completed, please remove any remaining Merge-Approved labels from this issue.

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

Friendly reminder to please merge your CL to branch 3029.  Thanks.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5a22d11ca8644fa56e56b981b0bf30055b1f4964

commit 5a22d11ca8644fa56e56b981b0bf30055b1f4964
Author: Nicolas Dossou-gbete <dgn@chromium.org>
Date: Fri Mar 17 11:00:07 2017

[Android] Fix flashing ripple on tab switch toolbar button

The ripple was initiated while in the tab switcher but invisible
because it's too dark, and is only visible for a short moment when
the tab is selected. This makes the ripple invisible while inside
the tab switcher.

BUG= 697455 

Review-Url: https://codereview.chromium.org/2734203002
Cr-Commit-Position: refs/heads/master@{#455121}
(cherry picked from commit e66cb66e93428dcd00ff059cc27d165b9361ba92)

Review-Url: https://codereview.chromium.org/2759433006 .
Cr-Commit-Position: refs/branch-heads/3029@{#257}
Cr-Branched-From: 939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}

[modify] https://crrev.com/5a22d11ca8644fa56e56b981b0bf30055b1f4964/chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarPhone.java