Make EditableCombobox Default Constructable

BUG=1108460

Change-Id: Ie5eb700075a15cc1cec52f500831115a161f100c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2364080Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Robert Liao <robliao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799912}

ui/views/BUILD.gn

@@ -334,6 +334,8 @@ component("views") {
     "controls/button/toggle_button.cc",
     "controls/combobox/combobox.cc",
     "controls/combobox/combobox_util.cc",
+    "controls/combobox/empty_combobox_model.cc",
+    "controls/combobox/empty_combobox_model.h",
     "controls/editable_combobox/editable_combobox.cc",
     "controls/focus_ring.cc",
     "controls/focusable_border.cc",

ui/views/controls/combobox/combobox.cc

@@ -32,6 +32,7 @@
 #include "ui/views/controls/button/button_controller.h"
 #include "ui/views/controls/combobox/combobox_listener.h"
 #include "ui/views/controls/combobox/combobox_util.h"
+#include "ui/views/controls/combobox/empty_combobox_model.h"
 #include "ui/views/controls/focus_ring.h"
 #include "ui/views/controls/focusable_border.h"
 #include "ui/views/controls/menu/menu_config.h"
@@ -51,23 +52,6 @@ namespace {
 // Used to indicate that no item is currently selected by the user.
 constexpr int kNoSelection = -1;
 
-// An empty model for a combo box.
-class EmptyComboboxModel final : public ui::ComboboxModel {
- public:
-  EmptyComboboxModel() = default;
-  EmptyComboboxModel(EmptyComboboxModel&) = delete;
-  EmptyComboboxModel& operator=(const EmptyComboboxModel&) = delete;
-  ~EmptyComboboxModel() override = default;
-
-  // ui::ComboboxModel:
-  int GetItemCount() const override { return 0; }
-  base::string16 GetItemAt(int index) const override {
-    NOTREACHED();
-    return base::string16();
-  }
-  int GetDefaultIndex() const override { return -1; }
-};
-
 SkColor GetTextColorForEnableState(const Combobox& combobox, bool enabled) {
   const int style = enabled ? style::STYLE_PRIMARY : style::STYLE_DISABLED;
   return style::GetColor(combobox, style::CONTEXT_TEXTFIELD, style);
@@ -248,7 +232,7 @@ class Combobox::ComboboxMenuModel : public ui::MenuModel {
 // Combobox, public:
 
 Combobox::Combobox(int text_context, int text_style)
-    : Combobox(std::make_unique<EmptyComboboxModel>()) {}
+    : Combobox(std::make_unique<internal::EmptyComboboxModel>()) {}
 
 Combobox::Combobox(std::unique_ptr<ui::ComboboxModel> model,
                    int text_context,

ui/views/controls/combobox/empty_combobox_model.cc

+// Copyright 2020 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/controls/combobox/empty_combobox_model.h"
+
+#include "base/notreached.h"
+#include "base/strings/string16.h"
+
+namespace views {
+namespace internal {
+
+EmptyComboboxModel::EmptyComboboxModel() = default;
+EmptyComboboxModel::~EmptyComboboxModel() = default;
+
+int EmptyComboboxModel::GetItemCount() const {
+  return 0;
+}
+
+base::string16 EmptyComboboxModel::GetItemAt(int index) const {
+  NOTREACHED();
+  return base::string16();
+}
+
+int EmptyComboboxModel::GetDefaultIndex() const {
+  return -1;
+}
+
+}  // namespace internal
+}  // namespace views

ui/views/controls/combobox/empty_combobox_model.h

+// Copyright 2020 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_CONTROLS_COMBOBOX_EMPTY_COMBOBOX_MODEL_H_
+#define UI_VIEWS_CONTROLS_COMBOBOX_EMPTY_COMBOBOX_MODEL_H_
+
+#include "ui/base/models/combobox_model.h"
+
+namespace views {
+namespace internal {
+
+// An empty model for a combo box.
+class EmptyComboboxModel final : public ui::ComboboxModel {
+ public:
+  EmptyComboboxModel();
+  EmptyComboboxModel(EmptyComboboxModel&) = delete;
+  EmptyComboboxModel& operator=(const EmptyComboboxModel&) = delete;
+  ~EmptyComboboxModel() override;
+
+  // ui::ComboboxModel:
+  int GetItemCount() const override;
+  base::string16 GetItemAt(int index) const override;
+  int GetDefaultIndex() const override;
+};
+
+}  // namespace internal
+}  // namespace views
+
+#endif  // UI_VIEWS_CONTROLS_COMBOBOX_EMPTY_COMBOBOX_MODEL_H_

ui/views/controls/editable_combobox/editable_combobox.cc

@@ -44,6 +44,7 @@
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/button/button_controller.h"
 #include "ui/views/controls/combobox/combobox_util.h"
+#include "ui/views/controls/combobox/empty_combobox_model.h"
 #include "ui/views/controls/menu/menu_config.h"
 #include "ui/views/controls/menu/menu_runner.h"
 #include "ui/views/controls/menu/menu_types.h"
@@ -301,6 +302,9 @@ class EditableCombobox::EditableComboboxPreTargetHandler
   DISALLOW_COPY_AND_ASSIGN(EditableComboboxPreTargetHandler);
 };
 
+EditableCombobox::EditableCombobox()
+    : EditableCombobox(std::make_unique<internal::EmptyComboboxModel>()) {}
+
 EditableCombobox::EditableCombobox(
     std::unique_ptr<ui::ComboboxModel> combobox_model,
     const bool filter_on_edit,
@@ -310,16 +314,13 @@ EditableCombobox::EditableCombobox(
     const int text_style,
     const bool display_arrow)
     : textfield_(new Textfield()),
-      combobox_model_(std::move(combobox_model)),
-      menu_model_(
-          std::make_unique<EditableComboboxMenuModel>(this,
-                                                      combobox_model_.get(),
-                                                      filter_on_edit,
-                                                      show_on_empty)),
       text_context_(text_context),
       text_style_(text_style),
       type_(type),
+      filter_on_edit_(filter_on_edit),
+      show_on_empty_(show_on_empty),
       showing_password_text_(type != Type::kPassword) {
+  SetModel(std::move(combobox_model));
   observer_.Add(textfield_);
   textfield_->set_controller(this);
   textfield_->SetFontList(GetFontList());
@@ -341,6 +342,13 @@ EditableCombobox::~EditableCombobox() {
   textfield_->set_controller(nullptr);
 }
 
+void EditableCombobox::SetModel(std::unique_ptr<ui::ComboboxModel> model) {
+  CloseMenu();
+  combobox_model_.swap(model);
+  menu_model_ = std::make_unique<EditableComboboxMenuModel>(
+      this, combobox_model_.get(), filter_on_edit_, show_on_empty_);
+}
+
 const base::string16& EditableCombobox::GetText() const {
   return textfield_->GetText();
 }

ui/views/controls/editable_combobox/editable_combobox.h

@@ -56,6 +56,8 @@ class VIEWS_EXPORT EditableCombobox
   static constexpr int kDefaultTextContext = style::CONTEXT_BUTTON;
   static constexpr int kDefaultTextStyle = style::STYLE_PRIMARY;
 
+  EditableCombobox();
+
   // |combobox_model|: The ComboboxModel that gives us the items to show in the
   // menu.
   // |filter_on_edit|: Whether to only show the items that are case-insensitive
@@ -66,16 +68,18 @@ class VIEWS_EXPORT EditableCombobox
   // |text_context| and |text_style|: Together these indicate the font to use.
   // |display_arrow|: Whether to display an arrow in the combobox to indicate
   // that there is a drop-down list.
-  EditableCombobox(std::unique_ptr<ui::ComboboxModel> combobox_model,
-                   bool filter_on_edit,
-                   bool show_on_empty,
-                   Type type = Type::kRegular,
-                   int text_context = kDefaultTextContext,
-                   int text_style = kDefaultTextStyle,
-                   bool display_arrow = true);
+  explicit EditableCombobox(std::unique_ptr<ui::ComboboxModel> combobox_model,
+                            bool filter_on_edit = false,
+                            bool show_on_empty = true,
+                            Type type = Type::kRegular,
+                            int text_context = kDefaultTextContext,
+                            int text_style = kDefaultTextStyle,
+                            bool display_arrow = true);
 
   ~EditableCombobox() override;
 
+  void SetModel(std::unique_ptr<ui::ComboboxModel> model);
+
   const base::string16& GetText() const;
   void SetText(const base::string16& text);
 
@@ -167,6 +171,12 @@ class VIEWS_EXPORT EditableCombobox
 
   const Type type_;
 
+  // Whether to adapt the items shown to the textfield content.
+  bool filter_on_edit_;
+
+  // Whether to show options when the textfield is empty.
+  bool show_on_empty_;
+
   // Set while the drop-down is showing.
   std::unique_ptr<MenuRunner> menu_runner_;
 

ui/views/controls/editable_combobox/editable_combobox_unittest.cc

@@ -829,5 +829,67 @@ TEST_F(EditableComboboxTest, NoCrashWithoutWidget) {
   combobox->RevealPasswords(true);
 }
 
+using EditableComboboxDefaultTest = ViewsTestBase;
+
+class ConfigurableComboboxModel final : public ui::ComboboxModel {
+ public:
+  explicit ConfigurableComboboxModel(bool* destroyed = nullptr)
+      : destroyed_(destroyed) {
+    if (destroyed_)
+      *destroyed_ = false;
+  }
+  ConfigurableComboboxModel(ConfigurableComboboxModel&) = delete;
+  ConfigurableComboboxModel& operator=(const ConfigurableComboboxModel&) =
+      delete;
+  ~ConfigurableComboboxModel() override {
+    if (destroyed_)
+      *destroyed_ = true;
+  }
+
+  // ui::ComboboxModel:
+  int GetItemCount() const override { return item_count_; }
+  base::string16 GetItemAt(int index) const override {
+    DCHECK_LT(index, item_count_);
+    return base::NumberToString16(index);
+  }
+
+  void SetItemCount(int item_count) { item_count_ = item_count; }
+
+ private:
+  bool* const destroyed_;
+  int item_count_ = 0;
+};
+
 }  // namespace
+
+TEST_F(EditableComboboxDefaultTest, Default) {
+  auto combobox = std::make_unique<EditableCombobox>();
+  EXPECT_EQ(0, combobox->GetItemCountForTest());
+}
+
+TEST_F(EditableComboboxDefaultTest, SetModel) {
+  std::unique_ptr<ConfigurableComboboxModel> model =
+      std::make_unique<ConfigurableComboboxModel>();
+  model->SetItemCount(42);
+  auto combobox = std::make_unique<EditableCombobox>();
+  combobox->SetModel(std::move(model));
+  EXPECT_EQ(42, combobox->GetItemCountForTest());
+}
+
+TEST_F(EditableComboboxDefaultTest, SetModelOverwrite) {
+  bool destroyed_first = false;
+  bool destroyed_second = false;
+  {
+    auto combobox = std::make_unique<EditableCombobox>();
+    combobox->SetModel(
+        std::make_unique<ConfigurableComboboxModel>(&destroyed_first));
+    ASSERT_FALSE(destroyed_first);
+    combobox->SetModel(
+        std::make_unique<ConfigurableComboboxModel>(&destroyed_second));
+    EXPECT_TRUE(destroyed_first);
+    ASSERT_FALSE(destroyed_second);
+  }
+  EXPECT_TRUE(destroyed_second);
+}
+
 }  // namespace views