Fix crash when clicking the close button on a closing infobar.

chrome/browser/tab_contents/infobar.cc

 // Copyright (c) 2011 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/tab_contents/infobar.h"
 
 #include <cmath>
 
 #include "build/build_config.h"
 #include "base/logging.h"
@@ skipping 83 matching lines @@
 void InfoBar::CloseSoon() {
   owner_ = NULL;
   MaybeDelete();
 }
 
 void InfoBar::AnimationProgressed(const ui::Animation* animation) {
   RecalculateHeights(false);
 }
 
 void InfoBar::RemoveInfoBar() {
-  if (!delegate_)
+  // If the user clicks the close button when the infobar is already closing
+  // (e.g. because this is the second click of a double-click on the button),
+  // |owner_| can be NULL here, in which case we don't want to call
+  // InfoBarDismissed() either (since this can lead to us double-recording
+  // dismissals).
+  if (!delegate_ || !owner_)
     return;
   delegate_->InfoBarDismissed();
   owner_->RemoveInfoBar(delegate_);
 }
 
 void InfoBar::SetBarTargetHeight(int height) {
   if (bar_target_height_ != height) {
     bar_target_height_ = height;
     RecalculateHeights(false);
   }
@@ skipping 60 matching lines @@
 void InfoBar::MaybeDelete() {
   if (!owner_ && delegate_ && (animation_.GetCurrentValue() == 0.0)) {
     if (container_)
       container_->RemoveInfoBar(this);
     delegate_->InfoBarClosed();
     delegate_ = NULL;
   }
 }
 
 #endif  // TOOLKIT_VIEWS || TOOLKIT_GTK