Separate phishing/SE ads/ SE landing interstitial UMA stats

chrome/browser/safe_browsing/safe_browsing_blocking_page.cc

Index: chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
diff --git a/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc b/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
index 101fa5b97495430a32a220672099acdf38941bad..8bc07e127713911ef67520bd249b03a90ba8cb9a 100644
--- a/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
@@ -542,7 +542,18 @@ std::string SafeBrowsingBlockingPage::GetMetricPrefix() const {
     case SB_REASON_HARMFUL:
       return primary_subresource ? "harmful_subresource" : "harmful";
     case SB_REASON_PHISHING:
-      return primary_subresource ? "phishing_subresource" : "phishing";
+      ThreatPatternType threat_pattern_type =
+          unsafe_resources_[0].threat_metadata.threat_pattern_type;
+      if (threat_pattern_type == ThreatPatternType::PHISHING ||
+          threat_pattern_type == ThreatPatternType::NONE)
+        return primary_subresource ? "phishing_subresource" : "phishing";
+      else if (threat_pattern_type == ThreatPatternType::SOCIAL_ENGINEERING_ADS)
+        return primary_subresource ? "social_engineering_ads_subresource"
+                                   : "social_engineering_ads";
+      else if (threat_pattern_type ==
+               ThreatPatternType::SOCIAL_ENGINEERING_LANDING)
+        return primary_subresource ? "social_engineering_landing_subresource"
+                                   : "social_engineering_landing";
   }
   NOTREACHED();
   return std::string();

[Nathan Parker, 2016/05/17 19:23:58]

Maybe this should return "unknown_interstitial_type" or some readable string. 
That way if SB starts sending weird enums we don't (yet) recognize, we'll at
least see the issue in UMA.

[Jialiu Lin, 2016/05/17 20:32:24]

Changed from std::string() to "unkown_metric_prefix". 
Though.. this function returns part of the UMA name, not a enum. So unless we
declare a group of interstitial.unkown_metric_prefix.* uma stats in
histograms.xml, it will not help in identifying issues. 
And this return is guarded by the NOTREACHED() statement before it, should not
get here anyway.