I will take this,but I am new to chromium so need guidance on what should be tested and if other locations also require changes(what would break because of this)

I have found this file
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/dom/NodeFilter.idl

Will start with above file and create a commit

Hi,

Please review the below code.

https://codereview.chromium.org/2884263002

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b2785c18771b5327f278df28152d1b9ae5b9ce98

commit b2785c18771b5327f278df28152d1b9ae5b9ce98
Author: tripta.g <tripta.g@samsung.com>
Date: Sun May 21 22:53:26 2017

NodeFilter#acceptNode argument node should not be optional

BUG= 701567 

Review-Url: https://codereview.chromium.org/2884263002
Cr-Commit-Position: refs/heads/master@{#473486}

[modify] https://crrev.com/b2785c18771b5327f278df28152d1b9ae5b9ce98/AUTHORS
[modify] https://crrev.com/b2785c18771b5327f278df28152d1b9ae5b9ce98/third_party/WebKit/Source/core/dom/NodeFilter.idl