Converts most of WorkspaceLayoutManager tests to use common code

ash/mus/test/ash_test_impl_mus.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_MUS_TEST_ASH_TEST_IMPL_MUS_H_
 #define ASH_MUS_TEST_ASH_TEST_IMPL_MUS_H_
 
 #include "ash/common/test/ash_test_impl.h"
 #include "ash/mus/test/wm_test_base.h"
 #include "base/macros.h"
@@ skipping 11 matching lines @@
 
   // AshTestImpl:
   void SetUp() override;
   void TearDown() override;
   bool SupportsMultipleDisplays() const override;
   void UpdateDisplay(const std::string& display_spec) override;
   std::unique_ptr<WindowOwner> CreateTestWindow(
       const gfx::Rect& bounds_in_screen,
       ui::wm::WindowType type,
       int shell_window_id) override;
+  std::unique_ptr<WindowOwner> CreateToplevelTestWindow(
+      const gfx::Rect& bounds_in_screen,
+      int shell_window_id) override;
   display::Display GetSecondaryDisplay() override;
   bool SetSecondaryDisplayPlacement(
       display::DisplayPlacement::Position position,
       int offset) override;
+  void ConfigureWidgetInitParamsForDisplay(
+      WmWindow* window,
+      views::Widget::InitParams* init_params) override;
+  void AddTransientChild(WmWindow* parent, WmWindow* window) override;
 
  private:
   // TODO(sky): fold WmTestBase directly into this class when no more subclasses
   // of WmTestBase.
   std::unique_ptr<WmTestBase> wm_test_base_;
 
   DISALLOW_COPY_AND_ASSIGN(AshTestImplMus);
 };
 
 }  // namespace mus
 }  // namespace ash
 
 #endif  // ASH_MUS_TEST_ASH_TEST_IMPL_MUS_H_