[sync] Prevent flash of error icon while loading syncSetup page

chrome/browser/ui/webui/settings/people_handler.h

Index: chrome/browser/ui/webui/settings/people_handler.h
diff --git a/chrome/browser/ui/webui/settings/people_handler.h b/chrome/browser/ui/webui/settings/people_handler.h
index 7b587f71633eb0597223b66936e8f18f8f80e7ed..be8ab4ea3a4f0308844ef236ef330d75c6b621dc 100644
--- a/chrome/browser/ui/webui/settings/people_handler.h
+++ b/chrome/browser/ui/webui/settings/people_handler.h
@@ -98,6 +98,8 @@ class PeopleHandler : public SettingsPageUIHandler,
   FRIEND_TEST_ALL_PREFIXES(PeopleHandlerNonCrosTest,
                            SubmitAuthWithInvalidUsername);
   FRIEND_TEST_ALL_PREFIXES(PeopleHandlerFirstSigninTest, DisplayBasicLogin);
+  FRIEND_TEST_ALL_PREFIXES(PeopleHandlerTest,
+                           AcquireSyncBlockerWhenLoadingSyncSettingsSubpage);
 
   // SettingsPageUIHandler implementation.
   void RegisterMessages() override;
@@ -174,6 +176,15 @@ class PeopleHandler : public SettingsPageUIHandler,
   // Suppresses any further signin promos, since the user has signed in once.
   void MarkFirstSetupComplete();
 
+  // If we're directly loading the sync setup page, we acquire a
+  // SetupInProgressHandle early in order to prevent a lapse in
+  // ProfileSyncService's "SetupInProgress" status. This lapse previously
+  // occured between when the sync confirmation dialog was closed and when the
+  // sync setup page hadn't yet fired the SyncSetupShowSetupUI event.
+  // InitializeSyncBlocker is responsible for checking if we're navigating to
+  // the setup page and acquiring the sync_blocker.
+  void InitializeSyncBlocker();
+
   // Weak pointer.
   Profile* profile_;