Add metrics for schemes of content setting exceptions

components/content_settings/core/common/content_settings_pattern.h

Index: components/content_settings/core/common/content_settings_pattern.h
diff --git a/components/content_settings/core/common/content_settings_pattern.h b/components/content_settings/core/common/content_settings_pattern.h
index b5b83529b00f92b431157744a22fa4e9abebb3bb..8db1eca18d00f3c78ff8543d79cdf7a407e19234 100644
--- a/components/content_settings/core/common/content_settings_pattern.h
+++ b/components/content_settings/core/common/content_settings_pattern.h
@@ -53,6 +53,16 @@ class ContentSettingsPattern {
     DISJOINT_ORDER_PRE = 2,
   };
 
+  enum SchemeType {

[Ilya Sherman, 2016/08/10 05:34:26]

Please document that this enum is used to back an UMA histogram, and should
therefore be treated as append-only.

[lshang, 2016/08/11 00:26:50]

Done.

+    SCHEME_WILDCARD,
+    SCHEME_HTTP,
+    SCHEME_HTTPS,
+    SCHEME_FILE,
+    SCHEME_CHROMEEXTENSION,
+    SCHEME_OTHER,
+    SCHEME_MAX,
+  };
+
   struct PatternParts {
     PatternParts();
     PatternParts(const PatternParts& other);
@@ -178,6 +188,9 @@ class ContentSettingsPattern {
   // Returns a std::string representation of this pattern.
   std::string ToString() const;
 
+  // Returns scheme type of pattern.
+  ContentSettingsPattern::SchemeType GetScheme() const;
+
   // Compares the pattern with a given |other| pattern and returns the
   // |Relation| of the two patterns.
   Relation Compare(const ContentSettingsPattern& other) const;