assistant: add ScopedAssistantInteractionSubscriber

Bug: None
Change-Id: I193dba8deb36be925b99d216b9ff28adcece660c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2268473
Auto-Submit: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Jeroen Dhollander <jeroendh@google.com>
Commit-Queue: Xiaohui Chen <xiaohuic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#782774}

ash/app_list/views/assistant/assistant_page_view_unittest.cc

@@ -233,11 +233,7 @@ class AssistantInteractionCounter
   }
 
   int interaction_count_ = 0;
-  ScopedObserver<
-      chromeos::assistant::Assistant,
-      chromeos::assistant::AssistantInteractionSubscriber,
-      &chromeos::assistant::Assistant::AddAssistantInteractionSubscriber,
-      &chromeos::assistant::Assistant::RemoveAssistantInteractionSubscriber>
+  chromeos::assistant::ScopedAssistantInteractionSubscriber
       interaction_observer_{this};
 };
 

ash/assistant/assistant_interaction_controller_impl_unittest.cc

@@ -41,14 +41,11 @@ constexpr bool kSuccessResult = true;
 class AssistantInteractionSubscriberMock
     : public chromeos::assistant::AssistantInteractionSubscriber {
  public:
-  explicit AssistantInteractionSubscriberMock(Assistant* service)
-      : service_(service) {
-    service_->AddAssistantInteractionSubscriber(this);
+  explicit AssistantInteractionSubscriberMock(Assistant* service) {
+    scoped_subscriber_.Add(service);
   }
 
-  ~AssistantInteractionSubscriberMock() override {
-    service_->RemoveAssistantInteractionSubscriber(this);
-  }
+  ~AssistantInteractionSubscriberMock() override = default;
 
   MOCK_METHOD(void,
               OnInteractionStarted,
@@ -56,7 +53,8 @@ class AssistantInteractionSubscriberMock
               (override));
 
  private:
-  Assistant* const service_;
+  chromeos::assistant::ScopedAssistantInteractionSubscriber scoped_subscriber_{
+      this};
 };
 
 class AssistantInteractionControllerImplTest : public AssistantAshTestBase {

ash/assistant/ui/main_stage/assistant_onboarding_view_unittest.cc

@@ -57,14 +57,11 @@ class MockAssistantInteractionSubscriber
     : public testing::NiceMock<
           chromeos::assistant::AssistantInteractionSubscriber> {
  public:
-  explicit MockAssistantInteractionSubscriber(Assistant* service)
-      : service_(service) {
-    service_->AddAssistantInteractionSubscriber(this);
+  explicit MockAssistantInteractionSubscriber(Assistant* service) {
+    scoped_subscriber_.Add(service);
   }
 
-  ~MockAssistantInteractionSubscriber() override {
-    service_->RemoveAssistantInteractionSubscriber(this);
-  }
+  ~MockAssistantInteractionSubscriber() override = default;
 
   MOCK_METHOD(void,
               OnInteractionStarted,
@@ -72,7 +69,8 @@ class MockAssistantInteractionSubscriber
               (override));
 
  private:
-  Assistant* service_;
+  chromeos::assistant::ScopedAssistantInteractionSubscriber scoped_subscriber_{
+      this};
 };
 
 // ScopedShowUi ----------------------------------------------------------------

chromeos/services/assistant/public/cpp/assistant_service.h

@@ -10,6 +10,7 @@
 
 #include "base/component_export.h"
 #include "base/observer_list_types.h"
+#include "base/scoped_observer.h"
 #include "chromeos/services/assistant/public/mojom/assistant_notification.mojom.h"
 #include "ui/accessibility/mojom/ax_assistant_structure.mojom.h"
 
@@ -371,6 +372,12 @@ class COMPONENT_EXPORT(ASSISTANT_SERVICE_PUBLIC) Assistant {
   virtual void ResumeTimer(const std::string& id) = 0;
 };
 
+using ScopedAssistantInteractionSubscriber =
+    ScopedObserver<Assistant,
+                   AssistantInteractionSubscriber,
+                   &Assistant::AddAssistantInteractionSubscriber,
+                   &Assistant::RemoveAssistantInteractionSubscriber>;
+
 // Main interface between browser and |chromeos::assistant::Service|.
 class COMPONENT_EXPORT(ASSISTANT_SERVICE_PUBLIC) AssistantService {
  public: