Remove more dead app list code.

ui/app_list/app_list_constants.h

Index: ui/app_list/app_list_constants.h
diff --git a/ui/app_list/app_list_constants.h b/ui/app_list/app_list_constants.h
index e23fa194a580c952d1ef210080fe30dc002c72ce..7e6cb28feb4a405ae1163d4bc53ec01e9c66646e 100644
--- a/ui/app_list/app_list_constants.h
+++ b/ui/app_list/app_list_constants.h
@@ -89,11 +89,6 @@ APP_LIST_EXPORT extern const char kSearchResultOpenDisplayTypeHistogram[];
 APP_LIST_EXPORT extern const char kSearchQueryLength[];
 APP_LIST_EXPORT extern const char kSearchResultDistanceFromOrigin[];
 
-#if defined(OS_LINUX)
-// The WM_CLASS name for the app launcher window on Linux.
-APP_LIST_EXPORT extern const char kAppListWMClass[];
-#endif
-
 // Returns the shadow values for a view at |z_height|.
 APP_LIST_EXPORT gfx::ShadowValue GetShadowForZHeight(int z_height);