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 975320ef416ee6fc56a8689f49952af6a382a82d..f68d171047a0acba72ddd526e5a1b4451004ef60 100644
--- a/chrome/browser/win/jumplist.h
+++ b/chrome/browser/win/jumplist.h
@@ -189,9 +189,6 @@ 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_;