Fixing remaining VC++ 2015 64-bit build breaks

content/child/npapi/webplugin_delegate_impl_win.cc

 // Copyright (c) 2012 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 "content/child/npapi/webplugin_delegate_impl.h"
 
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 576 matching lines @@
         base::TimeDelta::FromMilliseconds(kFlashWMUSERMessageThrottleDelayMs));
   }
 }
 
 // Schedule a windows message for delivery later.
 // static
 void WebPluginDelegateImpl::ThrottleMessage(WNDPROC proc, HWND hwnd,
                                             UINT message, WPARAM wParam,
                                             LPARAM lParam) {
   MSG msg;
-  msg.time = reinterpret_cast<DWORD>(proc);
+  // Cast through uintptr_t and then DWORD to make the truncation explicit.
+  msg.time = static_cast<DWORD>(reinterpret_cast<uintptr_t>(proc));
   msg.hwnd = hwnd;
   msg.message = message;
   msg.wParam = wParam;
   msg.lParam = lParam;
 
   ThrottleQueue* throttle_queue = g_throttle_queue.Pointer();
 
   throttle_queue->push_back(msg);
 
   if (throttle_queue->size() == 1) {
@@ skipping 874 matching lines @@
     case WM_RBUTTONUP:
       ::ReleaseCapture();
       break;
 
     default:
       break;
   }
 }
 
 }  // namespace content