mash: Convert AshPopupAlignmentDelegate to wm common types

ash/shelf/shelf.cc

Index: ash/shelf/shelf.cc
diff --git a/ash/shelf/shelf.cc b/ash/shelf/shelf.cc
index cbc1e15c4b9f37fb03aeeacba823d785f5afedbb..5b7b1ba0ee6e542571c9845b79d9234caf54a385 100644
--- a/ash/shelf/shelf.cc
+++ b/ash/shelf/shelf.cc
@@ -15,7 +15,6 @@
 #include "ash/common/shell_window_ids.h"
 #include "ash/focus_cycler.h"
 #include "ash/root_window_controller.h"
-#include "ash/root_window_settings.h"
 #include "ash/screen_util.h"
 #include "ash/shelf/shelf_delegate.h"
 #include "ash/shelf/shelf_layout_manager.h"
@@ -73,18 +72,6 @@ Shelf* Shelf::ForWindow(const aura::Window* window) {
   return shelf_widget ? shelf_widget->shelf() : nullptr;
 }
 
-// static
-Shelf* Shelf::ForDisplayId(int64_t display_id) {
-  for (aura::Window* window : Shell::GetInstance()->GetAllRootWindows()) {
-    RootWindowSettings* settings = GetRootWindowSettings(window);
-    if (settings->display_id == display_id && settings->controller) {
-      ShelfWidget* shelf_widget = settings->controller->shelf_widget();
-      return shelf_widget ? shelf_widget->shelf() : nullptr;
-    }
-  }
-  return nullptr;
-}
-
 void Shelf::SetAlignment(ShelfAlignment alignment) {
   if (alignment_ == alignment)
     return;