Migrate old settings for ContentSettingTypes with wildcard as secondary_pattern

components/content_settings/core/browser/host_content_settings_map.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.
 
 // Maps hostnames to custom content settings.  Written on the UI thread and read
 // on any thread.  One instance per profile.
 
 #ifndef COMPONENTS_CONTENT_SETTINGS_CORE_BROWSER_HOST_CONTENT_SETTINGS_MAP_H_
 #define COMPONENTS_CONTENT_SETTINGS_CORE_BROWSER_HOST_CONTENT_SETTINGS_MAP_H_
 
@@ skipping 261 matching lines @@
   void RemoveObserver(content_settings::Observer* observer);
 
   // Schedules any pending lossy website settings to be written to disk.
   void FlushLossyWebsiteSettings();
 
   // Passes ownership of |clock|.
   void SetPrefClockForTesting(scoped_ptr<base::Clock> clock);
 
  private:
   friend class base::RefCountedThreadSafe<HostContentSettingsMap>;
-  friend class HostContentSettingsMapTest_NonDefaultSettings_Test;
+  friend class HostContentSettingsMapTest_MigrateOldSettings_Test;
+
   friend class content_settings::TestUtils;
 
   typedef std::map<ProviderType, content_settings::ProviderInterface*>
       ProviderMap;
   typedef ProviderMap::iterator ProviderIterator;
   typedef ProviderMap::const_iterator ConstProviderIterator;
 
   ~HostContentSettingsMap() override;
 
   ContentSetting GetDefaultContentSettingFromProvider(
       ContentSettingsType content_type,
       content_settings::ProviderInterface* provider) const;
 
+  // Migrate old settings for those ContentSettingsType which previously
+  // would use the same pattern twice instead of using
+  // ContentSettingsPattern::Wildcard(). This has no impact on lookups using
+  // GetContentSetting (because Wildcard matches everything) but it has an
+  // impact when trying to change the existing content setting. We need to
+  // migrate the old-format keys.

[raymes, 2016/03/07 01:47:55]

I think we can rephrase this a bit because my explanation was probably not the
best :)

// Migrate old settings for ContentSettingsTypes which only use a primary
pattern.
// Settings which only used a primary pattern were inconsistent in what they did
// with the secondary pattern. Some stored a ContentSettingsPattern::Wildcard()
// whereas others stored the same pattern twice. This function migrates all such

// settings to use ContentSettingsPattern::Wildcard(). This allows us to make
the
// scoping code consistent across different settings.

[lshang, 2016/03/23 13:58:36]

Done.

+  // TODO(lshang): Remove this when clients have migrated. We should leave in
+  // some code to remove old-format settings for a long time.
+  void MigrateOldSettings();
+
   // Adds content settings for |content_type| and |resource_identifier|,
   // provided by |provider|, into |settings|. If |incognito| is true, adds only
   // the content settings which are applicable to the incognito mode and differ
   // from the normal mode. Otherwise, adds the content settings for the normal
   // mode.
   void AddSettingsForOneType(
       const content_settings::ProviderInterface* provider,
       ProviderType provider_type,
       ContentSettingsType content_type,
       const std::string& resource_identifier,
@@ skipping 56 matching lines @@
   ProviderMap content_settings_providers_;
 
   base::ThreadChecker thread_checker_;
 
   base::ObserverList<content_settings::Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(HostContentSettingsMap);
 };
 
 #endif  // COMPONENTS_CONTENT_SETTINGS_CORE_BROWSER_HOST_CONTENT_SETTINGS_MAP_H_