mash: Migrate SessionStateDelegate access to WmShell.

ash/wm/workspace/workspace_layout_manager_unittest.cc

Index: ash/wm/workspace/workspace_layout_manager_unittest.cc
diff --git a/ash/wm/workspace/workspace_layout_manager_unittest.cc b/ash/wm/workspace/workspace_layout_manager_unittest.cc
index 32cc02a2bdd215067fc949cc2505e6f7d551976f..f36032bfa0fcfdac54eac43657c672a939a3dc60 100644
--- a/ash/wm/workspace/workspace_layout_manager_unittest.cc
+++ b/ash/wm/workspace/workspace_layout_manager_unittest.cc
@@ -839,13 +839,13 @@ TEST_F(WorkspaceLayoutManagerSoloTest, NotResizeWhenScreenIsLocked) {
       window_bounds.ToString());
 
   // The window size should not get touched while we are in lock screen.
-  Shell::GetInstance()->session_state_delegate()->LockScreen();
+  WmShell::Get()->GetSessionStateDelegate()->LockScreen();
   ShelfLayoutManager* shelf_layout_manager = shelf->shelf_layout_manager();
   shelf_layout_manager->UpdateVisibilityState();
   EXPECT_EQ(window_bounds.ToString(), window->bounds().ToString());
 
   // Coming out of the lock screen the window size should still remain.
-  Shell::GetInstance()->session_state_delegate()->UnlockScreen();
+  WmShell::Get()->GetSessionStateDelegate()->UnlockScreen();
   shelf_layout_manager->UpdateVisibilityState();
   EXPECT_EQ(
       ScreenUtil::GetMaximizedWindowBoundsInParent(window.get()).ToString(),
@@ -881,9 +881,9 @@ class WorkspaceLayoutManagerBackdropTest : public test::AshTestBase {
 
   // Turn the top window back drop on / off.
   void ShowTopWindowBackdrop(bool show) {
-    std::unique_ptr<ash::WorkspaceLayoutManagerBackdropDelegate> backdrop;
+    std::unique_ptr<WorkspaceLayoutManagerBackdropDelegate> backdrop;
     if (show) {
-      backdrop.reset(new ash::WorkspaceBackdropDelegate(
+      backdrop.reset(new WorkspaceBackdropDelegate(
           WmWindowAura::Get(default_container_)));
     }
     GetWorkspaceLayoutManager(default_container_)