Retire ScopedObserver in /components/omnibox.

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=jdonnelly@chromium.org

Bug: 1145565
Change-Id: Id17e64fb0132a99c583e2670c5cd84fb2f34bc8d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2533154
Auto-Submit: Sigurður Ásgeirsson <siggi@chromium.org>
Reviewed-by: Justin Donnelly <jdonnelly@chromium.org>
Commit-Queue: Sigurður Ásgeirsson <siggi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826764}

components/omnibox/browser/favicon_cache.cc

@@ -31,11 +31,10 @@ bool FaviconCache::Request::operator<(const Request& rhs) const {
 FaviconCache::FaviconCache(favicon::FaviconService* favicon_service,
                            history::HistoryService* history_service)
     : favicon_service_(favicon_service),
-      history_observer_(this),
       mru_cache_(GetFaviconCacheSize()),
       responses_without_favicons_(GetFaviconCacheSize()) {
   if (history_service) {
-    history_observer_.Add(history_service);
+    history_observation_.Observe(history_service);
 
     favicons_changed_subscription_ =
         history_service->AddFaviconsChangedCallback(base::BindRepeating(

components/omnibox/browser/favicon_cache.h

@@ -13,7 +13,7 @@
 #include "base/containers/mru_cache.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/weak_ptr.h"
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "components/favicon_base/favicon_types.h"
 #include "components/history/core/browser/history_service.h"
@@ -132,8 +132,9 @@ class FaviconCache : public history::HistoryServiceObserver {
   // Non-owning pointer to a KeyedService.
   favicon::FaviconService* favicon_service_;
 
-  ScopedObserver<history::HistoryService, history::HistoryServiceObserver>
-      history_observer_{this};
+  base::ScopedObservation<history::HistoryService,
+                          history::HistoryServiceObserver>
+      history_observation_{this};
 
   base::CancelableTaskTracker task_tracker_;
   std::map<Request, std::list<FaviconFetchedCallback>> pending_requests_;

components/omnibox/browser/history_quick_provider_unittest.cc

@@ -76,9 +76,10 @@ void WaitForURLsDeletedObserver::OnURLsDeleted(
 void WaitForURLsDeletedNotification(history::HistoryService* history_service) {
   base::RunLoop runner;
   WaitForURLsDeletedObserver observer(&runner);
-  ScopedObserver<history::HistoryService, history::HistoryServiceObserver>
-      scoped_observer(&observer);
-  scoped_observer.Add(history_service);
+  base::ScopedObservation<history::HistoryService,
+                          history::HistoryServiceObserver>
+      scoped_observation(&observer);
+  scoped_observation.Observe(history_service);
   runner.Run();
 }
 

components/omnibox/browser/search_provider.cc

@@ -148,7 +148,7 @@ SearchProvider::SearchProvider(AutocompleteProviderClient* client,
 
   // |template_url_service| can be null in tests.
   if (template_url_service)
-    observer_.Add(template_url_service);
+    observation_.Observe(template_url_service);
 }
 
 // static

components/omnibox/browser/search_provider.h

@@ -17,7 +17,7 @@
 
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "components/omnibox/browser/answers_cache.h"
@@ -428,8 +428,8 @@ class SearchProvider : public BaseSearchProvider,
   AnswersCache answers_cache_;  // Cache for last answers seen.
   AnswersQueryData prefetch_data_;  // Data to use for query prefetching.
 
-  ScopedObserver<TemplateURLService, TemplateURLServiceObserver> observer_{
-      this};
+  base::ScopedObservation<TemplateURLService, TemplateURLServiceObserver>
+      observation_{this};
 };
 
 #endif  // COMPONENTS_OMNIBOX_BROWSER_SEARCH_PROVIDER_H_

components/omnibox/browser/shortcuts_backend.cc

@@ -83,7 +83,7 @@ ShortcutsBackend::ShortcutsBackend(
   if (!suppress_db)
     db_ = new ShortcutsDatabase(database_path);
   if (history_service)
-    history_service_observer_.Add(history_service);
+    history_service_observation_.Observe(history_service);
 }
 
 bool ShortcutsBackend::Init() {
@@ -190,7 +190,8 @@ ShortcutsDatabase::Shortcut::MatchCore ShortcutsBackend::MatchToMatchCore(
 }
 
 void ShortcutsBackend::ShutdownOnUIThread() {
-  history_service_observer_.RemoveAll();
+  if (history_service_observation_.IsObserving())
+    history_service_observation_.RemoveObservation();
 }
 
 void ShortcutsBackend::OnURLsDeleted(

components/omnibox/browser/shortcuts_backend.h

@@ -15,7 +15,7 @@
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "base/sequenced_task_runner.h"
 #include "base/strings/string16.h"
 #include "base/synchronization/lock.h"
@@ -170,8 +170,9 @@ class ShortcutsBackend : public RefcountedKeyedService,
   // This is a helper map for quick access to a shortcut by guid.
   GuidMap guid_map_;
 
-  ScopedObserver<history::HistoryService, history::HistoryServiceObserver>
-      history_service_observer_{this};
+  base::ScopedObservation<history::HistoryService,
+                          history::HistoryServiceObserver>
+      history_service_observation_{this};
 
   scoped_refptr<base::SequencedTaskRunner> main_runner_;
   scoped_refptr<base::SequencedTaskRunner> db_runner_;