Introduce incognito preference settings.

chrome/browser/extensions/test_extension_prefs.h

Index: chrome/browser/extensions/test_extension_prefs.h
diff --git a/chrome/browser/extensions/test_extension_prefs.h b/chrome/browser/extensions/test_extension_prefs.h
index 3220d7a263bdf34792ddecc54484364135217d3c..7d13eb03721b8f27d699ebaf25bc9b904c1dccbe 100644
--- a/chrome/browser/extensions/test_extension_prefs.h
+++ b/chrome/browser/extensions/test_extension_prefs.h
@@ -25,6 +25,9 @@ class TestExtensionPrefs {
 
   ExtensionPrefs* prefs() { return prefs_.get(); }
   PrefService* pref_service() { return pref_service_.get(); }
+  PrefService* incognito_pref_service() {
+    return incognito_pref_service_.get();
+  }
   const FilePath& temp_dir() const { return temp_dir_.path(); }
 
   // This will cause the ExtensionPrefs to be deleted and recreated, based on
@@ -49,6 +52,7 @@ class TestExtensionPrefs {
   FilePath preferences_file_;
   FilePath extensions_dir_;
   scoped_ptr<PrefService> pref_service_;
+  scoped_ptr<PrefService> incognito_pref_service_;
   scoped_ptr<ExtensionPrefs> prefs_;
 
  private: