Fix a potential access violation in the destructor of OmniboxViewWin.

chrome/browser/ui/views/omnibox/omnibox_view_win.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/ui/views/omnibox/omnibox_view_win.h"
 
 #include <algorithm>
 #include <locale>
 #include <string>
 
@@ skipping 511 matching lines @@
   // done so that we don't have to explicitly.
   if (!popup_window_mode_) {
     scoped_refptr<EditDropTarget> drop_target = new EditDropTarget(this);
     RegisterDragDrop(m_hWnd, drop_target.get());
   }
 }
 
 OmniboxViewWin::~OmniboxViewWin() {
   // Explicitly release the text object model now that we're done with it, and
   // before we free the library. If the library gets unloaded before this
-  // released, it becomes garbage.
-  text_object_model_->Release();
+  // released, it becomes garbage. Note that since text_object_model_ is lazy
+  // initialized, it may still be null.
+  if (text_object_model_)
+    text_object_model_->Release();
 
   // We balance our reference count and unpatch when the last instance has
   // been destroyed.  This prevents us from relying on the AtExit or static
   // destructor sequence to do our unpatching, which is generally fragile.
   g_paint_patcher.Pointer()->DerefPatch();
 }
 
 views::View* OmniboxViewWin::parent_view() const {
   return parent_view_;
 }
@@ skipping 2088 matching lines @@
   return (rect.left - client_rect.left) + (client_rect.right - rect.right);
 }
 
 int OmniboxViewWin::WidthNeededToDisplay(const string16& text) const {
   // Use font_.GetStringWidth() instead of
   // PosFromChar(location_entry_->GetTextLength()) because PosFromChar() is
   // apparently buggy. In both LTR UI and RTL UI with left-to-right layout,
   // PosFromChar(i) might return 0 when i is greater than 1.
   return font_.GetStringWidth(text) + GetHorizontalMargin();
 }