ash: Fix variable names and setters in ShelfLayoutManager and tests

ash/system/user/tray_user_unittest.cc

Index: ash/system/user/tray_user_unittest.cc
diff --git a/ash/system/user/tray_user_unittest.cc b/ash/system/user/tray_user_unittest.cc
index ee1a92aabcb0ab9e98dc49ada21e8d5365bf6c61..b0dcd3f3042b9c74808a22effcf7d20be1fd9505 100644
--- a/ash/system/user/tray_user_unittest.cc
+++ b/ash/system/user/tray_user_unittest.cc
@@ -47,14 +47,12 @@ class TrayUserTest : public ash::test::AshTestBase {
   void ClickUserItem(ui::test::EventGenerator* generator, int index);
 
   // Accessors to various system components.
-  ShelfLayoutManager* shelf() { return shelf_; }
   SystemTray* tray() { return tray_; }
   ash::test::TestSessionStateDelegate* delegate() { return delegate_; }
   ash::TrayUser* tray_user(int index) { return tray_user_[index]; }
   ash::TrayUserSeparator* tray_user_separator() { return tray_user_separator_; }
 
  private:
-  ShelfLayoutManager* shelf_;
   SystemTray* tray_;
   ash::test::TestSessionStateDelegate* delegate_;
 
@@ -69,15 +67,10 @@ class TrayUserTest : public ash::test::AshTestBase {
 };
 
 TrayUserTest::TrayUserTest()
-    : shelf_(NULL),
-      tray_(NULL),
-      delegate_(NULL),
-      tray_user_separator_(NULL) {
-}
+    : tray_(nullptr), delegate_(nullptr), tray_user_separator_(nullptr) {}
 
 void TrayUserTest::SetUp() {
   ash::test::AshTestBase::SetUp();
-  shelf_ = Shell::GetPrimaryRootWindowController()->GetShelfLayoutManager();
   tray_ = Shell::GetPrimaryRootWindowController()->GetSystemTray();
   delegate_ = static_cast<ash::test::TestSessionStateDelegate*>(
       ash::Shell::GetInstance()->session_state_delegate());
@@ -86,8 +79,9 @@ void TrayUserTest::SetUp() {
 void TrayUserTest::InitializeParameters(int users_logged_in,
                                         bool multiprofile) {
   // Show the shelf.
-  shelf()->LayoutShelf();
-  shelf()->SetAutoHideBehavior(SHELF_AUTO_HIDE_BEHAVIOR_NEVER);
+  Shelf* shelf = Shelf::ForPrimaryDisplay();
+  shelf->shelf_layout_manager()->LayoutShelf();
+  shelf->SetAutoHideBehavior(SHELF_AUTO_HIDE_BEHAVIOR_NEVER);
 
   // Set our default assumptions. Note that it is sufficient to set these
   // after everything was created.