The attached files...

Deleted: main.js 1.2 KB

main.js 1.2 KB View Download

Deleted: test.html 1.3 KB

test.html 1.3 KB View Download

Tested this issue on Windows 10 with chrome version #56.0.2924.87

These are the steps followed 

1. Downloaded attached files in same folder.
2. Installed chrome-remote-interface and png-js using npm
3. Loaded the test.html page in chrome
4. In the devtools -> console, for "scrollOffset" cmd it has given O/P as "10" and for "Page.startScreencast" cmd it has given "Uncaught ReferenceError: Page is not defined"

Seen the same behavior in FireFox browser too.

pdaniq@ could you please look into the attached screen-cast and let us know any steps i have missed while reproducing the scenario.

Thank You...

Deleted: Issue 687088.mp4 1.6 MB

	Issue 687088.mp4 1.6 MB View Download

you shouldn't just load test.html in chrome
run main.js using node, it will open chrome with the test.html for you
in CMD:
node main.js

make sure chrome is closed before running

this should give you output like this:
------------------------------------
expected offset: 90
metadata offset: 90

expected offset: 90
metadata offset: 80
!!!offset mismatch!!!

expected offset: 110
metadata offset: 110

expected offset: 260
metadata offset: 260

expected offset: 260
metadata offset: 250
!!!offset mismatch!!!
------------------------------------

if you dont see any output. close chrome and run it again.

Thank you for providing feedback. removing "Needs-Feedback" label.

As per comment#5, 
Installed node.js & NPM on Windows 10 machines & followed below steps:
1.Downloaded above both main.js & .html files & kept in a separate folder
2.Opened Terminal (Command prompt)
3.Typed node -v & observd the version
4.Typed npm -v & Observed npm version
5.Now typed node main.js & hit enter
6.Observed errors as displayed in the attached screenshot.

Hence unable to proceed further to test the issue.
pdaniq@Please find the attached scrrenshot & suggest us for further triaging the issue.

Thanks in advance!!

Deleted: 687088.PNG 179 KB

	687088.PNG 179 KB View Download

please run 
npm install png-js
npm install chrome-remote-interface

if chrome is not in your path (running "chrome" in cmd does not open chrome) please add it to your path using
set PATH=%PATH%;<path_to_chrome>
for example
set PATH=%PATH%;C:\Program Files (x86)\Google\Chrome\Application

close all browser instances
then run
node main.js

waiting to hear about your progress

Thank you for providing more feedback. Adding requester "jmukthavaram@chromium.org" to the cc list and removing "Needs-Feedback" label.

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

Thanks for the reply.
Able to reproduce the issue on Windows 10 using chrome stable-56.0.2924.87 & Canary-58.0.3028.0.
Observed all the mismatched results after running the 'node main.js' command via  terminal & same issue observed from M45 builds to latest chrome versions.Since it ia a non regression issue , marking it as 'Untriaged'.

Note: Earlier builds of M45 are getting crashed ,hence unable to test this issue.
Please find the attached screencast for reference.

Deleted: 687088-win10.mp4 2.3 MB

	687088-win10.mp4 2.3 MB View Download

This is low priority, closing due to lack of resources.