Allow building with VS 2015 Update 3 pre-release

chrome/app/delay_load_hook_win.cc

 // Copyright (c) 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 "chrome/app/delay_load_hook_win.h"
 
 #include <DelayIMP.h>
 
 #include "base/logging.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 
 // So long as these symbols are supplied to the final binary through an
 // object file (as opposed to indirectly through a library), these pointers
 // will override the CRT's symbols and direct the notifications to our hook.
 // Alternatively referencing the ChromeDelayLoadHook function somehow will
 // cause this declaration of these variables to take preference to the delay
 // load runtime's defaults (in delayimp.lib).
-PfnDliHook __pfnDliNotifyHook2 = ChromeDelayLoadHook;
-PfnDliHook __pfnDliFailureHook2 = ChromeDelayLoadHook;
+const PfnDliHook __pfnDliNotifyHook2 = ChromeDelayLoadHook;
+const PfnDliHook __pfnDliFailureHook2 = ChromeDelayLoadHook;
 
 
 namespace {
 
 FARPROC OnPreLoadLibrary(DelayLoadInfo* info) {
   // If the DLL name ends with "-delay.dll", this call is about one of our
   // custom import libraries. In this case we need to snip the suffix off,
   // and bind to the real DLL.
   std::string dll_name(info->szDll);
   const char kDelaySuffix[] = "-delay.dll";
@@ skipping 41 matching lines @@
 
     default:
       NOTREACHED() << "Impossible delay load notification.";
       break;
   }
 
   // Returning NULL causes the delay load machinery to perform default
   // processing for this notification.
   return NULL;
 }