Added default implementations of GetAcceleratorForCommandId.

ash/common/shelf/shelf_alignment_menu.cc

Index: ash/common/shelf/shelf_alignment_menu.cc
diff --git a/ash/common/shelf/shelf_alignment_menu.cc b/ash/common/shelf/shelf_alignment_menu.cc
index 574317a7e5f5597c6f13ea98d45076093b76eca0..43ee70d86958757ff4f52168f25eb30560149f02 100644
--- a/ash/common/shelf/shelf_alignment_menu.cc
+++ b/ash/common/shelf/shelf_alignment_menu.cc
@@ -45,12 +45,6 @@ bool ShelfAlignmentMenu::IsCommandIdEnabled(int command_id) const {
   return true;
 }
 
-bool ShelfAlignmentMenu::GetAcceleratorForCommandId(
-    int command_id,
-    ui::Accelerator* accelerator) const {
-  return false;
-}
-
 void ShelfAlignmentMenu::ExecuteCommand(int command_id, int event_flags) {
   WmShell* shell = WmShell::Get();
   switch (static_cast<MenuItem>(command_id)) {