[DevTools] Fix undocked DevToolsWindow closing.

chrome/browser/devtools/devtools_window.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 "chrome/browser/devtools/devtools_window.h"
 
 #include <algorithm>
 
 #include "base/json/json_reader.h"
 #include "base/metrics/histogram.h"
@@ skipping 287 matching lines @@
 
 WebContents* DevToolsWindow::ObserverWithAccessor::GetWebContents() {
   return web_contents();
 }
 
 // DevToolsWindow -------------------------------------------------------------
 
 const char DevToolsWindow::kDevToolsApp[] = "DevToolsApp";
 
 DevToolsWindow::~DevToolsWindow() {
+  life_stage_ = kClosing;
+
   UpdateBrowserWindow();
   UpdateBrowserToolbar();
 
   if (toolbox_web_contents_)
     delete toolbox_web_contents_;
 
   DevToolsWindows* instances = g_instances.Pointer();
   DevToolsWindows::iterator it(
       std::find(instances->begin(), instances->end(), this));
   DCHECK(it != instances->end());
@@ skipping 946 matching lines @@
       closure.Run();
     return;
   }
   load_completed_callback_ = closure;
 }
 
 bool DevToolsWindow::ForwardKeyboardEvent(
     const content::NativeWebKeyboardEvent& event) {
   return event_forwarder_->ForwardEvent(event);
 }