Fix chromium-style compile error that got in the tree since yesterday.

chrome/browser/browser_about_handler.cc

 // Copyright (c) 2011 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 "chrome/browser/browser_about_handler.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 68 matching lines @@
 
 using base::Time;
 using base::TimeDelta;
 
 #if defined(USE_TCMALLOC)
 // static
 AboutTcmallocOutputs* AboutTcmallocOutputs::GetInstance() {
   return Singleton<AboutTcmallocOutputs>::get();
 }
 
+AboutTcmallocOutputs::AboutTcmallocOutputs() {}
+
+AboutTcmallocOutputs::~AboutTcmallocOutputs() {}
+
 // Glue between the callback task and the method in the singleton.
 void AboutTcmallocRendererCallback(base::ProcessId pid, std::string output) {
   AboutTcmallocOutputs::GetInstance()->RendererCallback(pid, output);
 }
 #endif
 
 namespace {
 
 // The (alphabetized) paths used for the about pages.
 // Note: Keep these in sync with url_constants.h
@@ skipping 1023 matching lines @@
     // Run the dialog. This will re-use the existing one if it's already up.
     browser::ShowAboutIPCDialog();
     return true;
   }
 #endif
 
 #endif  // OFFICIAL_BUILD
 
   return false;
 }