Switch SupportsUserData uses to use unique_ptr.

ios/clean/chrome/app/steps/root_coordinator+application_step.mm

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ios/clean/chrome/app/steps/root_coordinator+application_step.h"
 
+#include "base/memory/ptr_util.h"
 #import "base/supports_user_data.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #import "ios/chrome/browser/web_state_list/web_state_list.h"
 #import "ios/clean/chrome/app/application_state.h"
 #import "ios/shared/chrome/browser/ui/browser_list/browser.h"
 #import "ios/shared/chrome/browser/ui/browser_list/browser_list.h"
 #import "ios/shared/chrome/browser/ui/coordinators/browser_coordinator+internal.h"
 #import "ios/web/public/navigation_manager.h"
 #include "ios/web/public/web_state/web_state.h"
 
@@ skipping 49 matching lines @@
   // Size the main view controller to fit the whole screen.
   [self.viewController.view setFrame:state.window.bounds];
 
   // Tell the application state to use this object to open URLs.
   state.URLOpener = self;
 
   // Show the window.
   state.window.hidden = NO;
 
   // Make sure this object stays alive.
-  state.persistentState->SetUserData(kRootCoordinatorContainerKey,
-                                     new RootCoordinatorContainer(self));
+  state.persistentState->SetUserData(
+      kRootCoordinatorContainerKey,
+      base::MakeUnique<RootCoordinatorContainer>(self));
 
   // Add a termination step to remove this object.
   [[state terminationSteps] addObject:[[StopRootCoordinator alloc] init]];
 }
 
 @end
 
 @implementation StopRootCoordinator
 
 - (BOOL)canRunInState:(ApplicationState*)state {
   return state.phase = APPLICATION_TERMINATING;
 }
 
 - (void)runInState:(ApplicationState*)state {
   state.persistentState->RemoveUserData(kRootCoordinatorContainerKey);
 }
 
 @end