Attempt 3 at a better touch tabstrip. There is still a bunch to do,

ui/views/view_model.h

 // 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.
 
 #ifndef UI_VIEWS_VIEW_MODEL_H_
 #define UI_VIEWS_VIEW_MODEL_H_
 #pragma once
 
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/logging.h"
 #include "ui/gfx/rect.h"
 #include "ui/views/views_export.h"
 
 namespace views {
 
 class View;
 
 // ViewModel is used to track an 'interesting' set of a views. Often times
 // during animations views are removed after a delay, which makes for tricky
 // coordinate conversion as you have to account for the possibility of the
@@ skipping 17 matching lines @@
   void Move(int index, int target_index);
 
   // Returns the number of views.
   int view_size() const { return static_cast<int>(entries_.size()); }
 
   // Removes and deletes all the views.
   void Clear();
 
   // Returns the view at the specified index.
   View* view_at(int index) const {
+    check_index(index);
     return entries_[index].view;
   }
 
   void set_ideal_bounds(int index, const gfx::Rect& bounds) {
+    check_index(index);
     entries_[index].ideal_bounds = bounds;
   }
 
   const gfx::Rect& ideal_bounds(int index) const {
+    check_index(index);
     return entries_[index].ideal_bounds;
   }
 
   // Returns the index of the specified view, or -1 if the view isn't in the
   // model.
   int GetIndexOfView(const View* view) const;
 
  private:
   struct Entry {
     Entry() : view(NULL) {}
 
     View* view;
     gfx::Rect ideal_bounds;
   };
   typedef std::vector<Entry> Entries;
 
+#if !defined(NDEBUG)
+  void check_index(int index) const {
+    DCHECK_LT(index, static_cast<int>(entries_.size()));
+    DCHECK_GE(index, 0);
+  }
+#else
+  void check_index(int index) const {}
+#endif
+
   Entries entries_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewModel);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_VIEW_MODEL_H_