cros: Move ash test files next to the classes under test

Historically //ash has been inconsistent in its placement of FooTestApi,
TestFooDelegate, MockFoo, etc.

Top-level ash OWNERS have decided that this sort of test code should
live in the same directory as Foo, not in //ash/test.

Move the files, collapse //ash/test/BUILD.gn into //ash/BUILD.gn and
add a note to //ash/README.md

[email protected]

Bug: none
Test: compiles, ash_unittests
Change-Id: I22b556742c37f9a414824d2ce48f3fa261949b71
Reviewed-on: https://chromium-review.googlesource.com/576142
Commit-Queue: James Cook <[email protected]>
Reviewed-by: Scott Violet <[email protected]>
Cr-Commit-Position: refs/heads/master@{#487559}
diff --git a/ash/shell_test_api.h b/ash/shell_test_api.h
new file mode 100644
index 0000000..a3418f4
--- /dev/null
+++ b/ash/shell_test_api.h
@@ -0,0 +1,45 @@
+// Copyright (c) 2012 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_SHELL_TEST_API_H_
+#define ASH_SHELL_TEST_API_H_
+
+#include <memory>
+
+#include "base/macros.h"
+
+namespace ash {
+class NativeCursorManagerAsh;
+class DragDropController;
+class MaximizeModeWindowManager;
+class PaletteDelegate;
+class ScreenPositionController;
+class Shell;
+class SystemGestureEventFilter;
+class WorkspaceController;
+
+// Accesses private data from a Shell for testing.
+class ShellTestApi {
+ public:
+  ShellTestApi();
+  explicit ShellTestApi(Shell* shell);
+
+  SystemGestureEventFilter* system_gesture_event_filter();
+  WorkspaceController* workspace_controller();
+  ScreenPositionController* screen_position_controller();
+  NativeCursorManagerAsh* native_cursor_manager_ash();
+  DragDropController* drag_drop_controller();
+  MaximizeModeWindowManager* maximize_mode_window_manager();
+
+  void SetPaletteDelegate(std::unique_ptr<PaletteDelegate> palette_delegate);
+
+ private:
+  Shell* shell_;  // not owned
+
+  DISALLOW_COPY_AND_ASSIGN(ShellTestApi);
+};
+
+}  // namespace ash
+
+#endif  // ASH_SHELL_TEST_API_H_