Reland: "Sync: Support multiple setup UIs."

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 4a98df8a598fc3ba6334f5dc12870158f381783e..d216dfb8069ae91bd424549d1d89ef80de0a4b13 100644
--- a/chrome/browser/ui/webui/settings/people_handler.h
+++ b/chrome/browser/ui/webui/settings/people_handler.h
@@ -33,6 +33,10 @@ namespace signin_metrics {
 enum class AccessPoint;
 }
 
+namespace sync_driver {
+class SyncSetupInProgressHandle;
+}
+
 namespace settings {
 
 class PeopleHandler : public SettingsPageUIHandler,
@@ -185,6 +189,9 @@ class PeopleHandler : public SettingsPageUIHandler,
   // Helper object used to wait for the sync backend to startup.
   std::unique_ptr<SyncStartupTracker> sync_startup_tracker_;
 
+  // Prevents Sync from running until configuration is complete.
+  std::unique_ptr<sync_driver::SyncSetupInProgressHandle> sync_blocker_;
+
   // Set to true whenever the sync configure UI is visible. This is used to tell
   // what stage of the setup wizard the user was in and to update the UMA
   // histograms in the case that the user cancels out.