Disable the hang dialog detector when showModalDialog is running.

content/common/view_messages.h

 // 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.
 
 // IPC messages for page rendering.
 // Multiply-included message file, hence no include guard.
 
 #include "base/process.h"
 #include "base/shared_memory.h"
 #include "content/common/content_export.h"
@@ skipping 1243 matching lines @@
 IPC_MESSAGE_ROUTED2(ViewHostMsg_ShowWidget,
                     int /* route_id */,
                     gfx::Rect /* initial_pos */)
 
 // Message to show a full screen widget.
 IPC_MESSAGE_ROUTED1(ViewHostMsg_ShowFullscreenWidget,
                     int /* route_id */)
 
 // This message is sent after ViewHostMsg_ShowView to cause the RenderView
 // to run in a modal fashion until it is closed.
-IPC_SYNC_MESSAGE_ROUTED0_0(ViewHostMsg_RunModal)
+IPC_SYNC_MESSAGE_ROUTED1_0(ViewHostMsg_RunModal,
+                           int /* opener_id */)
 
 // Indicates the renderer is ready in response to a ViewMsg_New or
 // a ViewMsg_CreatingNew_ACK.
 IPC_MESSAGE_ROUTED0(ViewHostMsg_RenderViewReady)
 
 // Indicates the renderer process is gone.  This actually is sent by the
 // browser process to itself, but keeps the interface cleaner.
 IPC_MESSAGE_ROUTED2(ViewHostMsg_RenderViewGone,
                     int, /* this really is base::TerminationStatus */
                     int /* exit_code */)
@@ skipping 753 matching lines @@
                     int  /* automation_id */)
 
 // Sent to the browser when the renderer detects it is blocked on a pepper
 // plugin message for too long. This is also sent when it becomes unhung
 // (according to the value of is_hung). The browser can give the user the
 // option of killing the plugin.
 IPC_MESSAGE_ROUTED3(ViewHostMsg_PepperPluginHung,
                     int /* plugin_child_id */,
                     FilePath /* path */,
                     bool /* is_hung */)