Adds AshTest

ash/common/test/ash_test_impl.h

Index: ash/common/test/ash_test_impl.h
diff --git a/ash/common/test/ash_test_impl.h b/ash/common/test/ash_test_impl.h
new file mode 100644
index 0000000000000000000000000000000000000000..0b5cf69973ddfa2cb2a8c1abf2ae9e401a943e29
--- /dev/null
+++ b/ash/common/test/ash_test_impl.h
@@ -0,0 +1,54 @@
+// 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_COMMON_TEST_ASH_TEST_IMPL_H_
+#define ASH_COMMON_TEST_ASH_TEST_IMPL_H_
+
+#include <memory>
+#include <string>
+
+#include "ui/display/manager/display_layout.h"
+#include "ui/views/widget/widget.h"
+#include "ui/wm/public/window_types.h"
+
+namespace display {
+class Display;
+}
+
+namespace gfx {
+class Rect;
+}
+
+namespace ash {
+
+class WindowOwner;
+class WmWindow;
+
+// Provides the real implementation of AshTest, see it for details.
+class AshTestImpl {
+ public:
+  virtual ~AshTestImpl() {}
+
+  // Factory function for creating AshTestImpl. Implemention that is used
+  // depends upon build dependencies.
+  static std::unique_ptr<AshTestImpl> Create();
+
+  // These functions mirror that of AshTest, see it for details.
+  virtual void SetUp() = 0;
+  virtual void TearDown() = 0;
+  virtual bool SupportsMultipleDisplays() const = 0;
+  virtual void UpdateDisplay(const std::string& display_spec) = 0;
+  virtual std::unique_ptr<WindowOwner> CreateTestWindow(
+      const gfx::Rect& bounds_in_screen,
+      ui::wm::WindowType type,
+      int shell_window_id) = 0;
+  virtual display::Display GetSecondaryDisplay() = 0;
+  virtual bool SetSecondaryDisplayPlacement(
+      display::DisplayPlacement::Position position,
+      int offset) = 0;
+};
+
+}  // namespace ash
+
+#endif  // ASH_COMMON_TEST_ASH_TEST_IMPL_H_