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

chrome/browser/extensions/extension_prefs.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_PREFS_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_PREFS_H_
 #pragma once
 
 #include <set>
 #include <string>
@@ skipping 364 matching lines @@
                                      const std::string& pref_key,
                                      ExtensionPrefsScope scope);
 
   // Returns true if currently no extension with higher precedence controls the
   // preference.
   bool CanExtensionControlPref(const std::string& extension_id,
                                const std::string& pref_key,
                                bool incognito);
 
   // Returns true if extension |extension_id| currently controls the
-  // preference.
+  // preference. If |from_incognito| is not NULL, looks at incognito preferences
+  // first, and |from_incognito| is set to true if the effective pref value is
+  // coming from the incognito preferences, false if it is coming from the
+  // normal ones.
   bool DoesExtensionControlPref(const std::string& extension_id,
                                 const std::string& pref_key,
-                                bool incognito);
+                                bool* from_incognito);
 
   // Returns true if there is an extension which controls the preference value
   //  for |pref_key| *and* it is specific to incognito mode.
   bool HasIncognitoPrefValue(const std::string& pref_key);
 
   // Clears incognito session-only content settings for all extensions.
   void ClearIncognitoSessionOnlyContentSettings();
 
   // Returns true if the extension was installed from the Chrome Web Store.
   bool IsFromWebStore(const std::string& extension_id) const;
@@ skipping 143 matching lines @@
   // Contains all the logic for handling the order for various extension
   // properties.
   scoped_ptr<ExtensionSorting> extension_sorting_;
 
   scoped_refptr<extensions::ContentSettingsStore> content_settings_store_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionPrefs);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_PREFS_H_