@felt, any suggestions on how to structure the code to support the quiet design?

This was my (disorganised) line of thinking:
+ Alter BaseBlockingPage constructor to check for a type so that the appropriate baseSafeBrowsingErrorUI can can be created. 
+ Amend SecurityInterstitialPage::GetHTMLContents to check for the type of interstitial and use the appropriate template

For the tests should I just add a section to: safe_browsing_blocking_page_test.cc

Thanks.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6483de8b9dab69e6b7f83d5239bb8ee009425bf1

commit 6483de8b9dab69e6b7f83d5239bb8ee009425bf1
Author: edwardjung <edwardjung@chromium.org>
Date: Thu May 25 16:23:28 2017

Add quiet safe browsing interstitials to chrome://interstitials for in browser testing

BUG= 716097 

Review-Url: https://codereview.chromium.org/2894243002
Cr-Commit-Position: refs/heads/master@{#474671}

[modify] https://crrev.com/6483de8b9dab69e6b7f83d5239bb8ee009425bf1/chrome/browser/BUILD.gn
[add] https://crrev.com/6483de8b9dab69e6b7f83d5239bb8ee009425bf1/chrome/browser/safe_browsing/test_safe_browsing_blocking_page_quiet.cc
[add] https://crrev.com/6483de8b9dab69e6b7f83d5239bb8ee009425bf1/chrome/browser/safe_browsing/test_safe_browsing_blocking_page_quiet.h
[modify] https://crrev.com/6483de8b9dab69e6b7f83d5239bb8ee009425bf1/chrome/browser/ui/webui/interstitials/interstitial_ui.cc
[modify] https://crrev.com/6483de8b9dab69e6b7f83d5239bb8ee009425bf1/chrome/browser/ui/webui/interstitials/interstitial_ui_browsertest.cc
[modify] https://crrev.com/6483de8b9dab69e6b7f83d5239bb8ee009425bf1/components/security_interstitials/core/browser/resources/interstitial_ui.html