Improve JumpList icon folders' naming style

chrome/browser/win/jumplist.h

Index: chrome/browser/win/jumplist.h
diff --git a/chrome/browser/win/jumplist.h b/chrome/browser/win/jumplist.h
index f41ce88aa9d7a444946105bac8638a6372747aad..27be9f22529f3b0158c712aa088eec98484adc0c 100644
--- a/chrome/browser/win/jumplist.h
+++ b/chrome/browser/win/jumplist.h
@@ -185,9 +185,6 @@ class JumpList : public sessions::TabRestoreServiceObserver,
   // App id to associate with the jump list.
   std::wstring app_id_;
 
-  // The directory which contains JumpList icons.
-  base::FilePath icon_dir_;
-
   // Timer for requesting delayed updates of the jumplist.
   base::OneShotTimer timer_;