Split mode incognito extension can get misleading pref changed events from regular mode

chrome/browser/extensions/extension_pref_value_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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_PREF_VALUE_MAP_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_PREF_VALUE_MAP_H_
 #pragma once
 
 #include <map>
 #include <set>
@@ skipping 98 matching lines @@
   // Returns true if an extension identified by |extension_id| controls the
   // preference. This means this extension has set a preference value and no
   // other extension with higher precedence overrides it.
   // Note that the this function does does not consider the existence of
   // policies. An extension is only really able to control a preference if
   // PrefService::Preference::IsExtensionModifiable() returns true as well.
   bool DoesExtensionControlPref(const std::string& extension_id,
                                 const std::string& pref_key,
                                 bool incognito) const;
 
+  // Returns true if an extension identified by |extension_id| controls the
+  // preference, *and* it is specific to incognito mode. This means this
+  // extension has set a preference value and no other extension with higher
+  // precedence overrides it.
+  // Note that the this function does does not consider the existence of
+  // policies. An extension is only really able to control a preference if
+  // PrefService::Preference::IsExtensionModifiable() returns true as well.
+  bool DoesExtensionControlIncognitoPref(const std::string& extension_id,
+                                         const std::string& pref_key) const;
+
   // Tell the store it's now fully initialized.
   void NotifyInitializationCompleted();
 
   // Registers the time when an extension |ext_id| is installed.
   void RegisterExtension(const std::string& ext_id,
                          const base::Time& install_time,
                          bool is_enabled);
 
   // Deletes all entries related to extension |ext_id|.
   void UnregisterExtension(const std::string& ext_id);
@@ skipping 52 matching lines @@
   // being destroyed. In tests, it isn't called, so the notification must
   // be done in the destructor. This bit tracks whether it has been done yet.
   bool destroyed_;
 
   ObserverList<Observer, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionPrefValueMap);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_PREF_VALUE_MAP_H_