Able to reproduce this issue on Mac OS 10.12 using chrome latest canary #59.0.3039.0. 

Bisect is not working on Mac due to  Issue 700097 , hence unable to provide the bisect. Will provide the hasbisect per revision when have access to Windows or Linux system with the bisect set up.

Manually inspecting the changelog: https://chromium.googlesource.com/chromium/src/+log/59.0.3037.0..59.0.3038.0?pretty=fuller&n=10000

allada@: Could this be related to https://codereview.chromium.org/2731633002 or https://codereview.chromium.org/2692653003.

Please re-assign if the changes are unrelated.

Ran has bisect per revision and this indeed points to https://codereview.chromium.org/2692653003.

I hope I'm not stepping on other's toes, as I know this issue has been assigned. Curiosity took over and I have shared my findings in the form of a CL to Code Review (https://codereview.chromium.org/2758183002).

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/33bc6b04dccef0bc2c1066dad202474e35e6dda7

commit 33bc6b04dccef0bc2c1066dad202474e35e6dda7
Author: james <james@apphaus.co.uk>
Date: Tue Mar 21 00:49:03 2017

DevTools: Fix Network panel warning icon display when offline/throttled

Fixes an issue whereby the warning icon on the tab for the Network panel would not appear when offline or the network was otherwised throttled.

This issue was a regression in https://codereview.chromium.org/2692653003.

The fix works in the Network panel and Performance panel when offline/throttling is changed.

The following issue  http://crbug.com/702070  prevents the warning icon from being displayed when emulating offline from the Service Workers pane within the Applications panel. https://codereview.chromium.org/2757093002 should fix this.

BUG= 700797 

Review-Url: https://codereview.chromium.org/2758183002
Cr-Commit-Position: refs/heads/master@{#458260}

[modify] https://crrev.com/33bc6b04dccef0bc2c1066dad202474e35e6dda7/AUTHORS
[modify] https://crrev.com/33bc6b04dccef0bc2c1066dad202474e35e6dda7/third_party/WebKit/Source/devtools/front_end/network/NetworkPanel.js

Tested the issue on Latest Dev# 59.0.3053.3 on Windows, Mac and Linux and found the issue to be fixed.
Observed the warning symbol adjacent to Network tab.
Hence adding TE-Verified Labels.
Note: Attaching a screenshot for reference.
Thank You.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2e7a430d8d88222c04ab3ffb0a143fa85b3cec5b

commit 2e7a430d8d88222c04ab3ffb0a143fa85b3cec5b
Author: allada <allada@chromium.org>
Date: Wed Mar 29 19:12:57 2017

[Devtools] Fixed network indicator icon for throttling

This patch fixes and reverts the changes caused here:
https://codereview.chromium.org/2692653003. When we moved the checks
into network it no longer was able to receive messages when changed from
some other panels like timeline or emulation if network was not loaded
yet (ie: lazy loaded).

R=dgozman,pfeldman@chromium.org
BUG= 700797 

Review-Url: https://codereview.chromium.org/2765443005
Cr-Commit-Position: refs/heads/master@{#460482}

[add] https://crrev.com/2e7a430d8d88222c04ab3ffb0a143fa85b3cec5b/third_party/WebKit/LayoutTests/http/tests/inspector/network/network-requestblocking-icon-expected.txt
[add] https://crrev.com/2e7a430d8d88222c04ab3ffb0a143fa85b3cec5b/third_party/WebKit/LayoutTests/http/tests/inspector/network/network-requestblocking-icon.html
[modify] https://crrev.com/2e7a430d8d88222c04ab3ffb0a143fa85b3cec5b/third_party/WebKit/Source/devtools/front_end/main/Main.js
[modify] https://crrev.com/2e7a430d8d88222c04ab3ffb0a143fa85b3cec5b/third_party/WebKit/Source/devtools/front_end/network/NetworkPanel.js