views: Extract MusViewsDelegate to its own file

I always have trouble finding it in aura_init.cc. Also, it will get
slightly more complex in a follow-up CL.

Make ViewsDelegate have default implementations for its last two
pure-virtual methods, since it has default impls for all the other
ones.

Bug: none
Change-Id: I544872bdbc8668c99c20c7759c25185df4ba6433
Reviewed-on: https://chromium-review.googlesource.com/1114215Reviewed-by: Michael Wasserman <msw@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570229}

ui/views/mus/BUILD.gn

@@ -24,6 +24,8 @@ jumbo_component("mus") {
     "mus_client_observer.h",
     "mus_export.h",
     "mus_property_mirror.h",
+    "mus_views_delegate.cc",
+    "mus_views_delegate.h",
     "pointer_watcher_event_router.cc",
     "pointer_watcher_event_router.h",
     "screen_mus.cc",

ui/views/mus/aura_init.cc

@@ -18,34 +18,11 @@
 #include "ui/base/material_design/material_design_controller.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/ui_base_paths.h"
-#include "ui/views/layout/layout_provider.h"
 #include "ui/views/mus/mus_client.h"
-#include "ui/views/views_delegate.h"
+#include "ui/views/mus/mus_views_delegate.h"
 
 namespace views {
 
-namespace {
-
-class MusViewsDelegate : public ViewsDelegate {
- public:
-  MusViewsDelegate() {}
-  ~MusViewsDelegate() override {}
-
- private:
-#if defined(OS_WIN)
-  HICON GetSmallWindowIcon() const override { return nullptr; }
-#endif
-  void OnBeforeWidgetInit(
-      Widget::InitParams* params,
-      internal::NativeWidgetDelegate* delegate) override {}
-
-  LayoutProvider layout_provider_;
-
-  DISALLOW_COPY_AND_ASSIGN(MusViewsDelegate);
-};
-
-}  // namespace
-
 AuraInit::InitParams::InitParams() : resource_file("views_mus_resources.pak") {}
 
 AuraInit::InitParams::~InitParams() = default;

ui/views/mus/mus_views_delegate.cc

+// Copyright 2018 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 "ui/views/mus/mus_views_delegate.h"
+
+namespace views {
+
+MusViewsDelegate::MusViewsDelegate() = default;
+
+MusViewsDelegate::~MusViewsDelegate() = default;
+
+}  // namespace views

ui/views/mus/mus_views_delegate.h

+// Copyright 2018 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 UI_VIEWS_MUS_MUS_VIEWS_DELEGATE_H_
+#define UI_VIEWS_MUS_MUS_VIEWS_DELEGATE_H_
+
+#include "base/macros.h"
+#include "ui/views/layout/layout_provider.h"
+#include "ui/views/mus/mus_export.h"
+#include "ui/views/views_delegate.h"
+
+namespace views {
+
+class VIEWS_MUS_EXPORT MusViewsDelegate : public ViewsDelegate {
+ public:
+  MusViewsDelegate();
+  ~MusViewsDelegate() override;
+
+ private:
+  LayoutProvider layout_provider_;
+
+  DISALLOW_COPY_AND_ASSIGN(MusViewsDelegate);
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_MUS_MUS_VIEWS_DELEGATE_H_

ui/views/views_delegate.cc

@@ -80,6 +80,10 @@ HICON ViewsDelegate::GetDefaultWindowIcon() const {
   return nullptr;
 }
 
+HICON ViewsDelegate::GetSmallWindowIcon() const {
+  return nullptr;
+}
+
 bool ViewsDelegate::IsWindowInMetro(gfx::NativeWindow window) const {
   return false;
 }
@@ -100,6 +104,10 @@ void ViewsDelegate::AddRef() {
 void ViewsDelegate::ReleaseRef() {
 }
 
+void ViewsDelegate::OnBeforeWidgetInit(
+    Widget::InitParams* params,
+    internal::NativeWidgetDelegate* delegate) {}
+
 base::TimeDelta ViewsDelegate::GetTextfieldPasswordRevealDuration() {
   return base::TimeDelta();
 }

ui/views/views_delegate.h

@@ -151,7 +151,7 @@ class VIEWS_EXPORT ViewsDelegate {
   // Retrieves the default window icon to use for windows if none is specified.
   virtual HICON GetDefaultWindowIcon() const;
   // Retrieves the small window icon to use for windows if none is specified.
-  virtual HICON GetSmallWindowIcon() const = 0;
+  virtual HICON GetSmallWindowIcon() const;
   // Returns true if the window passed in is in the Windows 8 metro
   // environment.
   virtual bool IsWindowInMetro(gfx::NativeWindow window) const;
@@ -171,7 +171,7 @@ class VIEWS_EXPORT ViewsDelegate {
 
   // Gives the platform a chance to modify the properties of a Widget.
   virtual void OnBeforeWidgetInit(Widget::InitParams* params,
-                                  internal::NativeWidgetDelegate* delegate) = 0;
+                                  internal::NativeWidgetDelegate* delegate);
 
   // Returns the password reveal duration for Textfield.
   virtual base::TimeDelta GetTextfieldPasswordRevealDuration();