[iOS] Should create IOSUserEventService as soon as possible

IOSUserEventService is not synchronous. To avoid to have the DCHECK in
ConsentAuditor::RecordGaiaConsent() failing, this service should be
created as soon as possible, to make sure it is correctly initialized
before using it.
With this fix, it is now possible to put back the DCHECK in
ConsentAuditor::RecordGaiaConsent().

Bug: 819176
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I66be7843eb3cc73686c07b0ffdee232c90dad7dd
Reviewed-on: https://chromium-review.googlesource.com/951484
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Reviewed-by: Martin Šrámek <msramek@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#541123}(cherry picked from commit 1f2f87f)
Reviewed-on: https://chromium-review.googlesource.com/953463
Reviewed-by: Jérôme Lebel <jlebel@chromium.org>
Cr-Commit-Position: refs/branch-heads/3359@{#72}
Cr-Branched-From: 66afc5e-refs/heads/master@{#540276}

Author: Jérôme Lebel

components/consent_auditor/consent_auditor.cc

@@ -8,7 +8,6 @@
 
 #include "base/metrics/histogram_macros.h"
 #include "base/values.h"
-#include "build/build_config.h"
 #include "components/consent_auditor/pref_names.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
@@ -111,14 +110,10 @@ void ConsentAuditor::RecordGaiaConsent(
   // FakeUserEventService doesn't have a sync bridge.
   // TODO(crbug.com/709094, crbug.com/761485): Remove this check when the store
   // initializes synchronously and is instantly ready to receive data.
-#if !defined(OS_IOS)
-  // TODO(crbug.com/819176): On iOS the sync is may not be ready if the user
-  // taps on "OK GOT IT" button too fast.
   DCHECK(!user_event_service_->GetSyncBridge() ||
          user_event_service_->GetSyncBridge()
              ->change_processor()
              ->IsTrackingMetadata());
-#endif
   user_event_service_->RecordUserEvent(std::move(specifics));
 }
 

ios/chrome/browser/browser_state/chrome_browser_state_manager_impl.cc

@@ -40,6 +40,7 @@
 #include "ios/chrome/browser/signin/gaia_cookie_manager_service_factory.h"
 #include "ios/chrome/browser/signin/signin_manager_factory.h"
 #include "ios/chrome/browser/sync/ios_chrome_profile_sync_service_factory.h"
+#include "ios/chrome/browser/sync/ios_user_event_service_factory.h"
 
 namespace {
 
@@ -223,6 +224,10 @@ void ChromeBrowserStateManagerImpl::DoFinalInitForServices(
       ->SetupInvalidationsOnProfileLoad(invalidation_service);
   ios::AccountReconcilorFactory::GetForBrowserState(browser_state);
   DesktopPromotionSyncServiceFactory::GetForBrowserState(browser_state);
+  // TODO(crbug.com/709094), TODO(crbug.com/761485): Remove this following line
+  // when UserEventService will be initialized synchronously. Until then, the
+  // service has to be created as early as possible.
+  IOSUserEventServiceFactory::GetForBrowserState(browser_state);
 }
 
 void ChromeBrowserStateManagerImpl::AddBrowserStateToCache(