Use checked observers for Assistant.

This is preferred over unchecked observers.

Bug: b:120097552
Change-Id: Id44822dce375e3400baa336fee3154ad99d18d7f
Reviewed-on: https://chromium-review.googlesource.com/c/1354569
Commit-Queue: David Black <dmblack@google.com>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611999}

ash/assistant/assistant_controller.h

@@ -140,7 +140,7 @@ class ASH_EXPORT AssistantController
 
   // The observer list should be initialized early so that sub-controllers may
   // register as observers during their construction.
-  base::ObserverList<AssistantControllerObserver>::Unchecked observers_;
+  base::ObserverList<AssistantControllerObserver> observers_;
 
   mojo::BindingSet<mojom::AssistantController> assistant_controller_bindings_;
 

ash/assistant/assistant_controller_observer.h

@@ -9,6 +9,7 @@
 #include <string>
 
 #include "base/macros.h"
+#include "base/observer_list_types.h"
 
 class GURL;
 
@@ -20,7 +21,9 @@ enum class DeepLinkType;
 }  // namespace util
 }  // namespace assistant
 
-class AssistantControllerObserver {
+// A checked observer which receives notification of changes to the
+// AssistantController.
+class AssistantControllerObserver : public base::CheckedObserver {
  public:
   // Invoked when the AssistantController has been fully constructed.
   virtual void OnAssistantControllerConstructed() {}
@@ -40,7 +43,7 @@ class AssistantControllerObserver {
 
  protected:
   AssistantControllerObserver() = default;
-  virtual ~AssistantControllerObserver() = default;
+  ~AssistantControllerObserver() override = default;
 
   DISALLOW_COPY_AND_ASSIGN(AssistantControllerObserver);
 };

ash/assistant/model/assistant_cache_model.h

@@ -44,7 +44,7 @@ class AssistantCacheModel {
 
   std::vector<AssistantSuggestionPtr> conversation_starters_;
 
-  base::ObserverList<AssistantCacheModelObserver>::Unchecked observers_;
+  base::ObserverList<AssistantCacheModelObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(AssistantCacheModel);
 };

ash/assistant/model/assistant_cache_model_observer.h

@@ -8,12 +8,14 @@
 #include <map>
 
 #include "base/macros.h"
+#include "base/observer_list_types.h"
 #include "chromeos/services/assistant/public/mojom/assistant.mojom.h"
 
 namespace ash {
 
-// An observer which receives notification of changes to the Assistant cache.
-class AssistantCacheModelObserver {
+// A checked observer which receives notification of changes to the Assistant
+// cache.
+class AssistantCacheModelObserver : public base::CheckedObserver {
  public:
   using AssistantSuggestion = chromeos::assistant::mojom::AssistantSuggestion;
 
@@ -22,7 +24,7 @@ class AssistantCacheModelObserver {
       const std::map<int, const AssistantSuggestion*>& conversation_starters) {}
 
  protected:
-  virtual ~AssistantCacheModelObserver() = default;
+  ~AssistantCacheModelObserver() override = default;
 };
 
 }  // namespace ash

ash/assistant/model/assistant_interaction_model.h

@@ -147,7 +147,7 @@ class AssistantInteractionModel {
   std::unique_ptr<AssistantResponse> pending_response_;
   std::shared_ptr<AssistantResponse> response_;
 
-  base::ObserverList<AssistantInteractionModelObserver>::Unchecked observers_;
+  base::ObserverList<AssistantInteractionModelObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(AssistantInteractionModel);
 };

ash/assistant/model/assistant_interaction_model_observer.h

@@ -10,6 +10,7 @@
 #include <vector>
 
 #include "base/macros.h"
+#include "base/observer_list_types.h"
 
 namespace ash {
 
@@ -19,9 +20,9 @@ enum class InputModality;
 enum class InteractionState;
 enum class MicState;
 
-// An observer which receives notification of changes to an Assistant
+// A checked observer which receives notification of changes to an Assistant
 // interaction.
-class AssistantInteractionModelObserver {
+class AssistantInteractionModelObserver : public base::CheckedObserver {
  public:
   // Invoked when the interaction state is changed.
   virtual void OnInteractionStateChanged(InteractionState interaction_state) {}
@@ -58,7 +59,7 @@ class AssistantInteractionModelObserver {
 
  protected:
   AssistantInteractionModelObserver() = default;
-  virtual ~AssistantInteractionModelObserver() = default;
+  ~AssistantInteractionModelObserver() override = default;
 
   DISALLOW_COPY_AND_ASSIGN(AssistantInteractionModelObserver);
 };

ash/assistant/model/assistant_screen_context_model.h

@@ -35,7 +35,7 @@ class AssistantScreenContextModel {
 
   ScreenContextRequestState request_state_ = ScreenContextRequestState::kIdle;
 
-  base::ObserverList<AssistantScreenContextModelObserver>::Unchecked observers_;
+  base::ObserverList<AssistantScreenContextModelObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(AssistantScreenContextModel);
 };

ash/assistant/model/assistant_screen_context_model_observer.h

@@ -6,12 +6,15 @@
 #define ASH_ASSISTANT_MODEL_ASSISTANT_SCREEN_CONTEXT_MODEL_OBSERVER_H_
 
 #include "base/macros.h"
+#include "base/observer_list_types.h"
 
 namespace ash {
 
 enum class ScreenContextRequestState;
 
-class AssistantScreenContextModelObserver {
+// A checked observer which receives notification of changes to the Assistant
+// screen context model state.
+class AssistantScreenContextModelObserver : public base::CheckedObserver {
  public:
   // Invoked when the screen context request state is changed.
   virtual void OnScreenContextRequestStateChanged(
@@ -19,7 +22,7 @@ class AssistantScreenContextModelObserver {
 
  protected:
   AssistantScreenContextModelObserver() = default;
-  virtual ~AssistantScreenContextModelObserver() = default;
+  ~AssistantScreenContextModelObserver() override = default;
 
   DISALLOW_COPY_AND_ASSIGN(AssistantScreenContextModelObserver);
 };

ash/assistant/model/assistant_ui_model.h

@@ -86,7 +86,7 @@ class AssistantUiModel {
 
   AssistantSource entry_point_ = AssistantSource::kUnspecified;
 
-  base::ObserverList<AssistantUiModelObserver>::Unchecked observers_;
+  base::ObserverList<AssistantUiModelObserver> observers_;
 
   // Usable work area for Assistant. Value is only meaningful when Assistant
   // UI exists.

ash/assistant/model/assistant_ui_model_observer.h

@@ -6,6 +6,7 @@
 #define ASH_ASSISTANT_MODEL_ASSISTANT_UI_MODEL_OBSERVER_H_
 
 #include "base/macros.h"
+#include "base/observer_list_types.h"
 #include "ui/gfx/geometry/rect.h"
 
 namespace ash {
@@ -14,8 +15,9 @@ enum class AssistantSource;
 enum class AssistantUiMode;
 enum class AssistantVisibility;
 
-// An observer which receives notification of changes to the Assistant UI model.
-class AssistantUiModelObserver {
+// A checked observer which receives notification of changes to the Assistant UI
+// model.
+class AssistantUiModelObserver : public base::CheckedObserver {
  public:
   // Invoked when the UI mode is changed.
   virtual void OnUiModeChanged(AssistantUiMode ui_mode) {}
@@ -34,7 +36,7 @@ class AssistantUiModelObserver {
 
  protected:
   AssistantUiModelObserver() = default;
-  virtual ~AssistantUiModelObserver() = default;
+  ~AssistantUiModelObserver() override = default;
 
   DISALLOW_COPY_AND_ASSIGN(AssistantUiModelObserver);
 };

ash/assistant/ui/dialog_plate/dialog_plate.h

@@ -41,7 +41,7 @@ enum class DialogPlateButtonId {
 
 // DialogPlateObserver ---------------------------------------------------------
 
-class DialogPlateObserver {
+class DialogPlateObserver : public base::CheckedObserver {
  public:
   // Invoked when the dialog plate button identified by |id| is pressed.
   virtual void OnDialogPlateButtonPressed(DialogPlateButtonId id) {}
@@ -50,7 +50,7 @@ class DialogPlateObserver {
   virtual void OnDialogPlateContentsCommitted(const std::string& text) {}
 
  protected:
-  virtual ~DialogPlateObserver() = default;
+  ~DialogPlateObserver() override = default;
 };
 
 // DialogPlate -----------------------------------------------------------------
@@ -124,7 +124,7 @@ class DialogPlate : public views::View,
   std::unique_ptr<ui::CallbackLayerAnimationObserver> animation_observer_;
   std::unique_ptr<AssistantQueryHistory::Iterator> query_history_iterator_;
 
-  base::ObserverList<DialogPlateObserver>::Unchecked observers_;
+  base::ObserverList<DialogPlateObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(DialogPlate);
 };