Refactor backdrop

ash/wm/maximize_mode/maximize_mode_backdrop_delegate_impl.h

Index: ash/wm/maximize_mode/maximize_mode_backdrop_delegate_impl.h
diff --git a/ash/wm/maximize_mode/maximize_mode_backdrop_delegate_impl.h b/ash/wm/maximize_mode/maximize_mode_backdrop_delegate_impl.h
new file mode 100644
index 0000000000000000000000000000000000000000..bec3517d2d60b6e2e08ebf65c69fe3d7e25bc99f
--- /dev/null
+++ b/ash/wm/maximize_mode/maximize_mode_backdrop_delegate_impl.h
@@ -0,0 +1,24 @@
+// Copyright 2017 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.
+
+#include "ash/wm/workspace/backdrop_delegate.h"
+
+#include "ash/ash_export.h"
+#include "base/macros.h"
+
+namespace ash {
+
+class ASH_EXPORT MaximizeModeBackdropDelegateImpl : public BackdropDelegate {

[James Cook, 2017/05/15 21:57:38]

Class docs please. (Like, why is this a public class rather than something local
to MaximizeModeWindowManager? Tests, right?)

optional: Also, could MaximizeModeWindowManager just implement BackdropDelegate?
Or do you think that makes the lifetimes of the delegate unclear?

[oshima, 2017/05/16 08:22:08]

By public class, you mean the ctor is public? I can create a factory method and
hide
this class for test, so I'm not sure if mentioning the test is really useful.

I can move the impl to MMWM, then just enter the maximized mode in the test.
WDYT?
The delegate is owned by the controller, and want to keep it that way especially
because it doesn't depend on any state of the MMWM.

[James Cook, 2017/05/16 15:12:14]

Yes, I meant have this class be in the .cc file for MMWM.

Keeping it owned by the controller sgtm.

[oshima, 2017/05/17 07:44:33]

Looks like the some of existing tests assume it's NOT in maximize mode, so i
just added comment.

+ public:
+  MaximizeModeBackdropDelegateImpl() {}

[James Cook, 2017/05/15 21:57:38]

nit: = default (and consider moving to .cc)

[oshima, 2017/05/16 08:22:08]

Done.

Is "= default" now recommended? Just double checking
because there were folks didn't like it because it's actually longer.

[James Cook, 2017/05/16 15:12:14]

I don't think the style guide has an opinion. I prefer it.

+  ~MaximizeModeBackdropDelegateImpl() override {}
+
+ protected:
+  bool HasBackdrop(WmWindow* window) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MaximizeModeBackdropDelegateImpl);
+};
+
+}  // namespace ash