[Password Manager Cleanup] Replaces NULL -> nullptr.

chrome/browser/password_manager/password_manager_browsertest.cc

 // Copyright 2013 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.
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/metrics/histogram_samples.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/path_service.h"
@@ skipping 172 matching lines @@
     infobar_is_being_shown_ = true;
   }
 
   void OnInfoBarRemoved(infobars::InfoBar* infobar, bool animate) override {
     infobar_is_being_shown_ = false;
   }
 
   void OnManagerShuttingDown(infobars::InfoBarManager* manager) override {
     ASSERT_EQ(infobar_service_, manager);
     infobar_service_->RemoveObserver(this);
-    infobar_service_ = NULL;
+    infobar_service_ = nullptr;
   }
 
   bool infobar_is_being_shown_;
   InfoBarService* infobar_service_;
 
   DISALLOW_COPY_AND_ASSIGN(InfoBarObserver);
 };
 
 class BubbleObserver : public PromptObserver {
  public:
@@ skipping 1404 matching lines @@
   // save it, but the script cannot trigger that just by assigning to the
   // field's value.
   std::string fill_and_back =
       "document.getElementById('password_field').value = 'random';"
       "document.getElementById('input_submit_button').click();"
       "window.history.back();";
   ASSERT_TRUE(content::ExecuteScript(RenderViewHost(), fill_and_back));
   observer.Wait();
   EXPECT_FALSE(prompt_observer->IsShowingPrompt());
 }