Ensure strikethrough font renders in omnibox on iOS 10.3

ios/chrome/browser/ui/omnibox/omnibox_view_ios.mm

Index: ios/chrome/browser/ui/omnibox/omnibox_view_ios.mm
diff --git a/ios/chrome/browser/ui/omnibox/omnibox_view_ios.mm b/ios/chrome/browser/ui/omnibox/omnibox_view_ios.mm
index 22c5022ec9f6e3f2ed15bd777b6fd50e9b51d248..b8f27c7827b4b88865b8509a265a46ac141b5e96 100644
--- a/ios/chrome/browser/ui/omnibox/omnibox_view_ios.mm
+++ b/ios/chrome/browser/ui/omnibox/omnibox_view_ios.mm
@@ -671,6 +671,13 @@ void OmniboxViewIOS::UpdateSchemeStyle(const gfx::Range& range) {
   DCHECK_NE(security_state::SECURE_WITH_POLICY_INSTALLED_CERT, security_level);
 
   if (security_level == security_state::DANGEROUS) {
+    // Workaround: Add an attribute to allow strikethough to apply on iOS 10.3.

[rohitrao (ping after 24h), 2017/04/06 14:51:21]

Should we only apply this attribute if running on 10.3 and above?  Is there any
chance this could break behavior on older OS versions?

+    // See https://crbug.com/699702 for discussion.
+    [attributing_display_string_
+        addAttribute:NSBaselineOffsetAttributeName
+               value:@0
+               range:NSMakeRange(0, [attributing_display_string_ length])];
+
     // Add a strikethrough through the scheme.
     [attributing_display_string_
         addAttribute:NSStrikethroughStyleAttributeName