Add metrics for schemes of content setting exceptions

components/content_settings/core/browser/host_content_settings_map.cc

Index: components/content_settings/core/browser/host_content_settings_map.cc
diff --git a/components/content_settings/core/browser/host_content_settings_map.cc b/components/content_settings/core/browser/host_content_settings_map.cc
index 6b56ae6e7f863dec90f9a3cc482015fefa96ccb3..f5a47a8b15b82776c2f59f6f1f7b1b47e11db571 100644
--- a/components/content_settings/core/browser/host_content_settings_map.cc
+++ b/components/content_settings/core/browser/host_content_settings_map.cc
@@ -173,7 +173,7 @@ HostContentSettingsMap::HostContentSettingsMap(PrefService* prefs,
 
   MigrateKeygenSettings();
 
-  RecordNumberOfExceptions();
+  RecordExceptionMetrics();
 }
 
 // static
@@ -497,7 +497,7 @@ void HostContentSettingsMap::MigrateKeygenSettings() {
   }
 }
 
-void HostContentSettingsMap::RecordNumberOfExceptions() {
+void HostContentSettingsMap::RecordExceptionMetrics() {
   for (const content_settings::WebsiteSettingsInfo* info :
        *content_settings::WebsiteSettingsRegistry::GetInstance()) {
     ContentSettingsType content_type = info->type();
@@ -507,6 +507,17 @@ void HostContentSettingsMap::RecordNumberOfExceptions() {
     GetSettingsForOneType(content_type, std::string(), &settings);
     size_t num_exceptions = 0;
     for (const ContentSettingPatternSource& setting_entry : settings) {
+      // Skip default settings.
+      if (setting_entry.primary_pattern == ContentSettingsPattern::Wildcard() &&
+          setting_entry.secondary_pattern ==
+              ContentSettingsPattern::Wildcard()) {
+        continue;
+      }
+
+      UMA_HISTOGRAM_ENUMERATION("ContentSettings.ExceptionScheme",
+                                setting_entry.primary_pattern.GetScheme(),
+                                ContentSettingsPattern::SCHEME_MAX);
+
       if (setting_entry.source == "preference")
         ++num_exceptions;
     }