Use mojo Shelf interfaces for both mash and classic ash.

ash/common/shelf/wm_shelf.cc

Index: ash/common/shelf/wm_shelf.cc
diff --git a/ash/common/shelf/wm_shelf.cc b/ash/common/shelf/wm_shelf.cc
index de85bfb6121d22ef94a3cb5f7e01d46f52f075cb..c34b282ba6ed0f057880c99059aa4627df939211 100644
--- a/ash/common/shelf/wm_shelf.cc
+++ b/ash/common/shelf/wm_shelf.cc
@@ -12,6 +12,7 @@
 #include "ash/common/shelf/shelf_widget.h"
 #include "ash/common/shelf/wm_shelf_observer.h"
 #include "ash/common/shell_window_ids.h"
+#include "ash/common/system/tray/system_tray_delegate.h"
 #include "ash/common/wm_lookup.h"
 #include "ash/common/wm_root_window_controller.h"
 #include "ash/common/wm_shell.h"
@@ -26,6 +27,33 @@ WmShelf* WmShelf::ForWindow(WmWindow* window) {
   return window->GetRootWindowController()->GetShelf();
 }
 
+// static
+bool WmShelf::CanChangeShelfAlignment() {
+  if (WmShell::Get()->system_tray_delegate()->IsUserSupervised())
+    return false;
+
+  LoginStatus login_status =
+      WmShell::Get()->system_tray_delegate()->GetUserLoginStatus();
+
+  switch (login_status) {
+    case LoginStatus::LOCKED:
+    // Shelf alignment changes can be requested while being locked, but will
+    // be applied upon unlock.
+    case LoginStatus::USER:
+    case LoginStatus::OWNER:
+      return true;
+    case LoginStatus::PUBLIC:
+    case LoginStatus::SUPERVISED:
+    case LoginStatus::GUEST:
+    case LoginStatus::KIOSK_APP:
+    case LoginStatus::NOT_LOGGED_IN:
+      return false;
+  }
+
+  NOTREACHED();
+  return false;
+}
+
 void WmShelf::CreateShelfWidget(WmWindow* root) {
   DCHECK(!shelf_widget_);
   WmWindow* shelf_container =
@@ -62,15 +90,13 @@ void WmShelf::InitializeShelf() {
   // When the shelf is created the alignment is unlocked. Chrome will update the
   // alignment later from preferences.
   alignment_ = SHELF_ALIGNMENT_BOTTOM;
-  // NOTE: The delegate may access WmShelf.
-  WmShell::Get()->shelf_delegate()->OnShelfCreated(this);
+  WmShell::Get()->shelf_controller()->NotifyShelfCreated(this);
 }
 
 void WmShelf::ShutdownShelf() {
   DCHECK(shelf_view_);
   shelf_locking_manager_.reset();
   shelf_view_ = nullptr;
-  WmShell::Get()->shelf_delegate()->OnShelfDestroyed(this);
 }
 
 bool WmShelf::IsShelfInitialized() const {
@@ -97,8 +123,8 @@ void WmShelf::SetAlignment(ShelfAlignment alignment) {
   alignment_ = alignment;
   // The ShelfWidget notifies the ShelfView of the alignment change.
   shelf_widget_->OnShelfAlignmentChanged();
-  WmShell::Get()->shelf_delegate()->OnShelfAlignmentChanged(this);
   shelf_layout_manager_->LayoutShelf();
+  WmShell::Get()->shelf_controller()->NotifyShelfAlignmentChanged(this);
   WmShell::Get()->NotifyShelfAlignmentChanged(GetWindow()->GetRootWindow());
 }
 
@@ -142,7 +168,7 @@ void WmShelf::SetAutoHideBehavior(ShelfAutoHideBehavior auto_hide_behavior) {
     return;
 
   auto_hide_behavior_ = auto_hide_behavior;
-  WmShell::Get()->shelf_delegate()->OnShelfAutoHideBehaviorChanged(this);
+  WmShell::Get()->shelf_controller()->NotifyShelfAutoHideBehaviorChanged(this);
   WmShell::Get()->NotifyShelfAutoHideBehaviorChanged(
       GetWindow()->GetRootWindow());
 }