Add metrics for schemes of content setting exceptions

components/content_settings/core/common/content_settings_pattern.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Patterns used in content setting rules.
 
 #ifndef COMPONENTS_CONTENT_SETTINGS_CORE_COMMON_CONTENT_SETTINGS_PATTERN_H_
 #define COMPONENTS_CONTENT_SETTINGS_CORE_COMMON_CONTENT_SETTINGS_PATTERN_H_
 
 #include <string>
@@ skipping 35 matching lines @@
   //   Pattern A and B have an intersection. But pattern A has a higher
   //   precedence than pattern B for URLs that are matched by both pattern.
   enum Relation {
     DISJOINT_ORDER_POST = -2,
     SUCCESSOR = -1,
     IDENTITY = 0,
     PREDECESSOR = 1,
     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);
     ~PatternParts();
 
     // Lowercase string of the URL scheme to match. This string is empty if the
     // |is_scheme_wildcard| flag is set.
     std::string scheme;
 
     // True if the scheme wildcard is set.
@@ skipping 105 matching lines @@
 
   // True if |url| matches this pattern.
   bool Matches(const GURL& url) const;
 
   // True if this pattern matches all hosts (i.e. it has a host wildcard).
   bool MatchesAllHosts() const;
 
   // 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;
 
   // Returns true if the pattern and the |other| pattern are identical.
   bool operator==(const ContentSettingsPattern& other) const;
 
   // Returns true if the pattern and the |other| pattern are not identical.
   bool operator!=(const ContentSettingsPattern& other) const;
 
@@ skipping 27 matching lines @@
       const ContentSettingsPattern::PatternParts& other_parts);
 
   ContentSettingsPattern(const PatternParts& parts, bool valid);
 
   PatternParts parts_;
 
   bool is_valid_;
 };
 
 #endif  // COMPONENTS_CONTENT_SETTINGS_CORE_COMMON_CONTENT_SETTINGS_PATTERN_H_