Using the per-revision bisect providing the bisect results,
Good build: 61.0.3132.0 (Revision: 479901).
Bad build: 61.0.3132.0 (Revision: 480259).

You are probably looking for a change made after 479981 (known good), but no later than 479982 (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/f5f880c3d9d32f6925c211cd4836701cd2a3cbb2..0721d307c2e650409d287b02ddeeed4d1635b086?pretty=fuller&n=100

From the CL above, assigning the issue to the concern owner 

@dschuyler- Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.

Suspect : https://chromium.googlesource.com/chromium/src/+/0721d307c2e650409d287b02ddeeed4d1635b086

Thanks!

It looks like it's this line resetting the tap:
https://cs.chromium.org/chromium/src/chrome/browser/resources/settings/controls/settings_toggle_button.js?type=cs&q=settings_toggle_button&sq=package:chromium&l=76

scottchen@ removing that line will fix the toggle, but the comment suggests that will break keyboard handling.

Trying to find a fix right now. Could we consider merging to M62 instead?

After much testing, found out there are 2 issues:

1) the video in the bug report shows the tab doesn't react to drag. Notice how the user moved the mouse upward before releasing on the first drag - this is causing some invisible element or white-space/next-line characters to be highlighted, so on the next drag, the browser is actually trying to copy that text instead of dragging the toggle. The solution would be to collapse all text selection on mouse-down on the toggle, assuming that doesn't impact any actual use-case.

2) the tap reset is sometimes bouncing the toggle back to its original value, running the reset on the next cycle with setTimeout() seems to fix that issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/648e3c74a557cc8944188fd7e2cd658e29a8da4c

commit 648e3c74a557cc8944188fd7e2cd658e29a8da4c
Author: Scott Chen <scottchen@chromium.org>
Date: Fri Sep 08 01:34:08 2017

MD Settings: prevent text selection while dragging toggles.

Currently it is possible to accidentally select text while dragging
paper-toggle-buttons, which will cause confusing behaviors on the 
next toggle drag. This CL prevents accidental text selection, as well 
as fixing a flaky issue in which the toggle value gets reset after the drag.

Bug:  761959 
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I3dc3a478831376c1c9d62a5bdd52323a72267e80
Reviewed-on: https://chromium-review.googlesource.com/656522
Reviewed-by: Dave Schuyler <dschuyler@chromium.org>
Commit-Queue: Scott Chen <scottchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#500475}
[modify] https://crrev.com/648e3c74a557cc8944188fd7e2cd658e29a8da4c/chrome/browser/resources/settings/controls/settings_toggle_button.js
[modify] https://crrev.com/648e3c74a557cc8944188fd7e2cd658e29a8da4c/chrome/browser/resources/settings/settings_shared_css.html

Approving merge to M62. Branch: 3202

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b39e03700309e14f03bdcc97e7c8eba447560349

commit b39e03700309e14f03bdcc97e7c8eba447560349
Author: Scott Chen <scottchen@chromium.org>
Date: Fri Sep 08 23:32:21 2017

MD Settings: prevent text selection while dragging toggles.

Currently it is possible to accidentally select text while dragging
paper-toggle-buttons, which will cause confusing behaviors on the 
next toggle drag. This CL prevents accidental text selection, as well 
as fixing a flaky issue in which the toggle value gets reset after the drag.

Bug:  761959 
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I3dc3a478831376c1c9d62a5bdd52323a72267e80
Reviewed-on: https://chromium-review.googlesource.com/656522
Reviewed-by: Dave Schuyler <dschuyler@chromium.org>
Commit-Queue: Scott Chen <scottchen@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#500475}(cherry picked from commit 648e3c74a557cc8944188fd7e2cd658e29a8da4c)
Reviewed-on: https://chromium-review.googlesource.com/658264
Reviewed-by: Scott Chen <scottchen@chromium.org>
Cr-Commit-Position: refs/branch-heads/3202@{#104}
Cr-Branched-From: fa6a5d87adff761bc16afc5498c3f5944c1daa68-refs/heads/master@{#499098}
[modify] https://crrev.com/b39e03700309e14f03bdcc97e7c8eba447560349/chrome/browser/resources/settings/controls/settings_toggle_button.js
[modify] https://crrev.com/b39e03700309e14f03bdcc97e7c8eba447560349/chrome/browser/resources/settings/settings_shared_css.html

Tested the issue using latest #63.0.3212.0 on Linux Ubuntu 14.04, Win 7 as per the steps mentioned in comment #0. Able to drag 'Toggle' button using mouse pointer.

Please find the screencast. Hence adding Verified labels.

Thanks!!

Deleted: Sep 11 2017 7_11 PM.webm 1.9 MB

	Sep 11 2017 7_11 PM.webm 1.9 MB View Download

Rechecked the above issue on window 8 OS with dev build : 62.0.3202.18 and latest canary chrome build : 63.0.3213.0 and the issue is still reproducible.Kindly refer attached screen cast for reference.

Deleted: Actual_video.mp4 486 KB

	Actual_video.mp4 486 KB View Download

looking at the video, it appears that the second time you're trying to drag (at 0:06) you started dragging from outside the toggle element, and when you drag it selected text instead. 

From then on, when you're trying to drag *anywhere* in the window with text selected, the intended behavior would be to copy and move the text somewhere, which is why the toggle isn't moving (and this behavior is working as intended).

As a side note, the WebUI team reached consensus to stop supporting dragging of toggles, so in the near future toggles will only be clickable and not draggable.