Retire ScopedObserver in /components/search.

ScopedObserver is being deprecated in favor of two new classes:
- base::ScopedObservation for observers that only ever observe
  a single source.
- base::ScopedMultiSourceObservation for observers that do or may
  observe more than a single source.

This CL was uploaded by git cl split.

R=kmilka@chromium.org

Bug: 1145565
Change-Id: Ib3a00c095ae3210e9ca78c073685b48863388d03
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2532659
Auto-Submit: Sigurður Ásgeirsson <siggi@chromium.org>
Reviewed-by: Kyle Milka <kmilka@chromium.org>
Commit-Queue: Sigurður Ásgeirsson <siggi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826763}

components/search/repeatable_queries/repeatable_queries_service.cc

@@ -10,7 +10,7 @@
 #include "base/bind.h"
 #include "base/json/json_writer.h"
 #include "base/metrics/histogram_functions.h"
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "base/stl_util.h"
 #include "base/values.h"
 #include "components/history/core/browser/history_service.h"
@@ -84,7 +84,7 @@ class RepeatableQueriesService::SigninObserver
                  base::RepeatingClosure callback)
       : identity_manager_(identity_manager), callback_(std::move(callback)) {
     if (identity_manager_) {
-      identity_manager_observer_.Add(identity_manager_);
+      identity_manager_observation_.Observe(identity_manager_);
     }
   }
   ~SigninObserver() override = default;
@@ -103,8 +103,9 @@ class RepeatableQueriesService::SigninObserver
     callback_.Run();
   }
 
-  ScopedObserver<signin::IdentityManager, signin::IdentityManager::Observer>
-      identity_manager_observer_{this};
+  base::ScopedObservation<signin::IdentityManager,
+                          signin::IdentityManager::Observer>
+      identity_manager_observation_{this};
   // May be nullptr in tests.
   signin::IdentityManager* const identity_manager_;
   base::RepeatingClosure callback_;

components/search/search_provider_observer.cc

@@ -11,7 +11,7 @@ SearchProviderObserver::SearchProviderObserver(TemplateURLService* service,
       is_google_(search::DefaultSearchProviderIsGoogle(service_)),
       callback_(std::move(callback)) {
   if (service_) {
-    service_observer_.Add(service_);
+    service_observation_.Observe(service_);
   }
 }
 
@@ -29,6 +29,7 @@ void SearchProviderObserver::OnTemplateURLServiceChanged() {
 
 void SearchProviderObserver::OnTemplateURLServiceShuttingDown() {
   DCHECK(service_);
-  service_observer_.Remove(service_);
+  DCHECK(service_observation_.IsObservingSource(service_));
+  service_observation_.RemoveObservation();
   service_ = nullptr;
 }

components/search/search_provider_observer.h

@@ -5,7 +5,7 @@
 #ifndef COMPONENTS_SEARCH_SEARCH_PROVIDER_OBSERVER_H_
 #define COMPONENTS_SEARCH_SEARCH_PROVIDER_OBSERVER_H_
 
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "components/search_engines/template_url_service.h"
 #include "components/search_engines/template_url_service_observer.h"
 
@@ -25,8 +25,8 @@ class SearchProviderObserver : public TemplateURLServiceObserver {
   void OnTemplateURLServiceChanged() override;
   void OnTemplateURLServiceShuttingDown() override;
 
-  ScopedObserver<TemplateURLService, TemplateURLServiceObserver>
-      service_observer_{this};
+  base::ScopedObservation<TemplateURLService, TemplateURLServiceObserver>
+      service_observation_{this};
   // May be nullptr in tests.
   TemplateURLService* service_;
   bool is_google_;