Only show a warning for frames pointing at UwS URLs, not resources.
Where "frames" applies to the top-level frame, <iframe>'s, and <frame>'s.
Augmented SafeBrowsingBlockingPageBrowserTest to run for all 3 of MALWARE/PHISHING/UNWANTED threats.
BUG=439043
TEST=
A) New SafeBrowsingServiceTest.UnwantedImgIgnored test doesn't pass without corresponding ui_manager.cc change.
B) All SafeBrowsingBlockingPageBrowserTest augmented to run for UNWANTED_URL and PHISHING threats as well pass.
C) Manually verified that an iframe/frame/main_frame pointing to an Unwanted site triggers an interstitial, yet an image inclusion doesn't.
Review URL: https://codereview.chromium.org/
770503004
Cr-Commit-Position: refs/heads/master@{#307636}