Retire ScopedObserver in /components/ukm.

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=bcwhite@chromium.org

Bug: 1145565
Change-Id: I7abefcdf0a512108ecd78ff910f59b9c116db74d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2533173
Commit-Queue: Brian White <bcwhite@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Auto-Submit: Sigurður Ásgeirsson <siggi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826414}

components/ukm/observers/history_delete_observer.cc

@@ -13,7 +13,7 @@ HistoryDeleteObserver::~HistoryDeleteObserver() {}
 void HistoryDeleteObserver::ObserveServiceForDeletions(
     history::HistoryService* history_service) {
   if (history_service)
-    history_observer_.Add(history_service);
+    history_observations_.AddObservation(history_service);
 }
 
 void HistoryDeleteObserver::OnURLsDeleted(
@@ -25,7 +25,7 @@ void HistoryDeleteObserver::OnURLsDeleted(
 
 void HistoryDeleteObserver::HistoryServiceBeingDeleted(
     history::HistoryService* history_service) {
-  history_observer_.Remove(history_service);
+  history_observations_.RemoveObservation(history_service);
 }
 
 }  // namespace ukm

components/ukm/observers/history_delete_observer.h

@@ -7,7 +7,7 @@
 
 #include <set>
 
-#include "base/scoped_observer.h"
+#include "base/scoped_multi_source_observation.h"
 #include "components/history/core/browser/history_service.h"
 #include "components/history/core/browser/history_service_observer.h"
 
@@ -34,8 +34,9 @@ class HistoryDeleteObserver : public history::HistoryServiceObserver {
 
  private:
   // Tracks observed history services, for cleanup.
-  ScopedObserver<history::HistoryService, history::HistoryServiceObserver>
-      history_observer_{this};
+  base::ScopedMultiSourceObservation<history::HistoryService,
+                                     history::HistoryServiceObserver>
+      history_observations_{this};
 
   DISALLOW_COPY_AND_ASSIGN(HistoryDeleteObserver);
 };

components/ukm/observers/ukm_consent_state_observer.cc

@@ -18,7 +18,7 @@ using unified_consent::UrlKeyedDataCollectionConsentHelper;
 
 namespace ukm {
 
-UkmConsentStateObserver::UkmConsentStateObserver() : sync_observer_(this) {}
+UkmConsentStateObserver::UkmConsentStateObserver() = default;
 
 UkmConsentStateObserver::~UkmConsentStateObserver() {
   for (const auto& entry : consent_helpers_) {
@@ -55,7 +55,7 @@ void UkmConsentStateObserver::StartObserving(syncer::SyncService* sync_service,
 
   consent_helper->AddObserver(this);
   consent_helpers_[sync_service] = std::move(consent_helper);
-  sync_observer_.Add(sync_service);
+  sync_observations_.AddObservation(sync_service);
   UpdateUkmAllowedForAllProfiles(false);
 }
 
@@ -149,7 +149,8 @@ void UkmConsentStateObserver::OnSyncShutdown(syncer::SyncService* sync) {
     found->second->RemoveObserver(this);
     consent_helpers_.erase(found);
   }
-  sync_observer_.Remove(sync);
+  DCHECK(sync_observations_.IsObservingSource(sync));
+  sync_observations_.RemoveObservation(sync);
   previous_states_.erase(sync);
   UpdateUkmAllowedForAllProfiles(/*must_purge=*/false);
 }

components/ukm/observers/ukm_consent_state_observer.h

@@ -7,7 +7,7 @@
 
 #include <map>
 
-#include "base/scoped_observer.h"
+#include "base/scoped_multi_source_observation.h"
 #include "components/sync/driver/sync_service.h"
 #include "components/sync/driver/sync_service_observer.h"
 #include "components/unified_consent/url_keyed_data_collection_consent_helper.h"
@@ -69,8 +69,9 @@ class UkmConsentStateObserver
   bool CheckPreviousStatesAllowExtensionUkm();
 
   // Tracks observed sync services, for cleanup.
-  ScopedObserver<syncer::SyncService, syncer::SyncServiceObserver>
-      sync_observer_;
+  base::ScopedMultiSourceObservation<syncer::SyncService,
+                                     syncer::SyncServiceObserver>
+      sync_observations_{this};
 
   // State data about profiles that we need to remember.
   struct ProfileState {