Chrome Version: (copy from chrome://version)
OS: (e.g. Win10, MacOS 10.12, etc...)

What steps will reproduce the problem?
(1) open mytextarea.com, put focus in input box, 
(2) switch to other tab. 
(3) switch back to previous tab.

What is the expected result?
In this case, OS should fire "chrome.input.ime.onSurroundingTextChanged " event as well. 

What happens instead?
It doesn't fire.



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If this is a regression (i.e., worked before), please consider using the
bisect tool (https://www.chromium.org/developers/bisect-builds-py) to help
us identify the root cause and more rapidly triage the issue.

For graphics-related bugs, please copy/paste the contents of the about:gpu
page at the end of this report.