[DevTools] Delete old toolbox on debug reload.

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 839 matching lines @@
 }
 
 void DevToolsWindow::WebContentsCreated(WebContents* source_contents,
                                         int opener_render_frame_id,
                                         const base::string16& frame_name,
                                         const GURL& target_url,
                                         WebContents* new_contents) {
   if (target_url.SchemeIs(content::kChromeDevToolsScheme) &&
       target_url.path().rfind("toolbox.html") != std::string::npos) {
     CHECK(can_dock_);
+    if (toolbox_web_contents_)
+      delete toolbox_web_contents_;
     toolbox_web_contents_ = new_contents;
   }
 }
 
 void DevToolsWindow::CloseContents(WebContents* source) {
   CHECK(is_docked_);
   life_stage_ = kClosing;
   UpdateBrowserWindow();
   // In case of docked main_web_contents_, we own it so delete here.
   // Embedding DevTools window will be deleted as a result of
@@ skipping 331 matching lines @@
       closure.Run();
     return;
   }
   load_completed_callback_ = closure;
 }
 
 bool DevToolsWindow::ForwardKeyboardEvent(
     const content::NativeWebKeyboardEvent& event) {
   return event_forwarder_->ForwardEvent(event);
 }