Fixing remaining VC++ 2015 64-bit build breaks

chrome/browser/hang_monitor/hung_plugin_action.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 <windows.h>
 
 #include "chrome/browser/hang_monitor/hung_plugin_action.h"
 
 #include "base/metrics/histogram.h"
 #include "base/version.h"
@@ skipping 105 matching lines @@
               NULL, title, message, chrome::MESSAGE_BOX_TYPE_QUESTION) ==
           chrome::MESSAGE_BOX_RESULT_YES) {
         *action = HungWindowNotification::HUNG_WINDOW_TERMINATE_PROCESS;
       } else {
         // If the user choses to ignore the hung window warning, the
         // message timeout for this window should be doubled. We only
         // double the timeout property on the window if the property
         // exists. The property is deleted if the window becomes
         // responsive.
         continue_hang_detection = false;
-#pragma warning(disable:4311)
+#pragma warning(disable : 4311 4302)

[Nico, 2015/11/16 21:31:07]

should these warning pragmas have a comment that explains why they're safe to
do?

[brucedawson, 2015/11/17 00:24:39]

Yes. I copied over the warning from the previous file, adding the word
'truncation' to make the type of warning more explicit.

I also modified the layout of the #pragma warning on line 136 to make it
consistent.

[Nico, 2015/11/17 00:30:27]

Hm, this now says that it's a truncation, but not why that's ok. Is this snippet
only built in 32-bit builds?

[brucedawson, 2015/11/18 01:58:11]

Okay, better fix now. TetProp/GetProp take/return a HANDLE, so HandleToUint32
can be used, and some #pragmas can be removed.

There is no *actual* truncation because an int is being stored and retrieved, so
HandleToUint32 is safe.

The warnings on the reverse process (int to HANDLE) can wait for bug 554200 (I
just added a reminder).

         int child_window_message_timeout =
             reinterpret_cast<int>(GetProp(
                 hung_window, HungWindowDetector::kHungChildWindowTimeout));
-#pragma warning(default:4311)
+#pragma warning(default : 4311 4302)
         if (child_window_message_timeout) {
           child_window_message_timeout *= 2;
 #pragma warning(disable:4312)
           SetProp(hung_window, HungWindowDetector::kHungChildWindowTimeout,
                   reinterpret_cast<HANDLE>(child_window_message_timeout));
 #pragma warning(default:4312)
         }
       }
       current_hung_plugin_window_ = NULL;
     }
@@ skipping 34 matching lines @@
 void CALLBACK HungPluginAction::HungWindowResponseCallback(HWND target_window,
                                                            UINT message,
                                                            ULONG_PTR data,
                                                            LRESULT result) {
   HungPluginAction* instance = reinterpret_cast<HungPluginAction*>(data);
   DCHECK(NULL != instance);
   if (NULL != instance) {
     instance->OnWindowResponsive(target_window);
   }
 }