Separate ash::test::DisplayManagerTestApi from ash

ash/wm/workspace/workspace_window_resizer_unittest.cc

Index: ash/wm/workspace/workspace_window_resizer_unittest.cc
diff --git a/ash/wm/workspace/workspace_window_resizer_unittest.cc b/ash/wm/workspace/workspace_window_resizer_unittest.cc
index 03643567e3f3cffbe6052dbc51868e279d3404de..886985caf1385246742b2cd43ad3d3286b3dbdac 100644
--- a/ash/wm/workspace/workspace_window_resizer_unittest.cc
+++ b/ash/wm/workspace/workspace_window_resizer_unittest.cc
@@ -601,7 +601,7 @@ TEST_P(WorkspaceWindowResizerTest, Edge) {
   EXPECT_EQ(root_windows[0], window_->GetRootWindow());
   // Window is wide enough not to get docked right away.
   window_->SetBoundsInScreen(gfx::Rect(800, 10, 400, 60),
-                             ScreenUtil::GetSecondaryDisplay());
+                             display_manager()->GetSecondaryDisplay());
   EXPECT_EQ(root_windows[1], window_->GetRootWindow());
   {
     EXPECT_EQ("800,10 400x60", window_->GetBoundsInScreen().ToString());
@@ -818,7 +818,8 @@ TEST_P(WorkspaceWindowResizerTest, DontDragOffBottomWithMultiDisplay) {
 
   // Positions the secondary display at the bottom the primary display.
   Shell::GetInstance()->display_manager()->SetLayoutForCurrentDisplays(
-      test::CreateDisplayLayout(display::DisplayPlacement::BOTTOM, 0));
+      test::CreateDisplayLayout(display_manager(),
+                                display::DisplayPlacement::BOTTOM, 0));
 
   {
     window_->SetBounds(gfx::Rect(100, 200, 300, 20));