Fix renderer crash when a file chooser is closed after navigating away from...

chrome/renderer/render_view.cc

 // Copyright (c) 2006-2008 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/renderer/render_view.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 2590 matching lines @@
 
 void RenderView::OnInstallMissingPlugin() {
   // This could happen when the first default plugin is deleted.
   if (first_default_plugin_ == NULL)
     return;
   first_default_plugin_->InstallMissingPlugin();
 }
 
 void RenderView::OnFileChooserResponse(
          const std::vector<std::wstring>& file_names) {
+  // This could happen if we navigated to a different page before the user
+  // closed the chooser.
+  if (!file_chooser_.get())
+    return;
+
   file_chooser_->OnFileChoose(file_names);
   file_chooser_.reset();
 }
 
 void RenderView::OnEnableViewSourceMode() {
   if (!webview())
     return;
   WebFrame* main_frame = webview()->GetMainFrame();
   if (!main_frame)
     return;
@@ skipping 299 matching lines @@
   DCHECK(audio_renderers_.Lookup(stream_id) != NULL);
   Send(new ViewHostMsg_SetAudioVolume(routing_id_, stream_id, left, right));
 }
 
 void RenderView::OnResize(const gfx::Size& new_size,
                           const gfx::Rect& resizer_rect) {
   if (webview())
     webview()->HideAutofillPopup();
   RenderWidget::OnResize(new_size, resizer_rect);
 }