Code: bool IsIDNComponentSafe(base::StringPiece16 label) {
  return g_idn_spoof_checker.Get().Check(label);
 }

Vulnerability Type: 
CWE ID: CWE-20
Summary: Insufficient Policy Enforcement in Omnibox in Google Chrome prior to 58.0.3029.81 for Mac, Windows, and Linux, and 58.0.3029.83 for Android, allowed a remote attacker to perform domain spoofing via IDN homographs in a crafted domain name.
Commit Message: Block domain labels made of Cyrillic letters that look alike Latin

Block a label made entirely of Latin-look-alike Cyrillic letters when the TLD is not an IDN (i.e. this check is ON only for TLDs like 'com', 'net', 'uk', but not applied for IDN TLDs like рф.

BUG=683314
TEST=components_unittests --gtest_filter=U*IDN*

Review-Url: https://codereview.chromium.org/2683793010
Cr-Commit-Position: refs/heads/master@{#459226}