Context:
You need to share an item from an application the set tint color.
The example I used to reproduce is Google Play Newsstand.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cfa7526644a9bf91d4f119448a216fa690116ec5

commit cfa7526644a9bf91d4f119448a216fa690116ec5
Author: olivierrobin <olivierrobin@chromium.org>
Date: Fri Feb 17 17:27:47 2017

Set "Cancel" button blue in iOS Share extension

At the moment, the button can be tinted by host app.
Always set color to blue.

BUG= 693600 

Review-Url: https://codereview.chromium.org/2701743004
Cr-Commit-Position: refs/heads/master@{#451328}

[modify] https://crrev.com/cfa7526644a9bf91d4f119448a216fa690116ec5/ios/chrome/share_extension/share_extension_view.mm

Tested Set "Cancel" button blue in iOS Share extension, 
Share an item from an application (safari, Google Play Newsstand).
Looks good.