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

ui/views/view_model.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 "ui/views/view_model.h"
 
 #include "base/logging.h"
 #include "ui/views/view.h"
 
 namespace views {
 
 ViewModel::ViewModel() {
 }
 
 ViewModel::~ViewModel() {
   // view are owned by their parent, no need to delete them.
 }
 
 void ViewModel::Add(View* view, int index) {
+  DCHECK_LE(index, static_cast<int>(entries_.size()));
+  DCHECK_GE(index, 0);
   Entry entry;
   entry.view = view;
   entries_.insert(entries_.begin() + index, entry);
 }
 
 void ViewModel::Remove(int index) {
   if (index == -1)
     return;
 
+  check_index(index);
   entries_.erase(entries_.begin() + index);
 }
 
 void ViewModel::Move(int index, int target_index) {
   if (index == target_index)
     return;
   Entry entry(entries_[index]);
   entries_.erase(entries_.begin() + index);
   entries_.insert(entries_.begin() + target_index, entry);
 }
 
 void ViewModel::Clear() {
   Entries entries;
   entries.swap(entries_);
   for (size_t i = 0; i < entries.size(); ++i)
     delete entries[i].view;
 }
 
 int ViewModel::GetIndexOfView(const View* view) const {
   for (size_t i = 0; i < entries_.size(); ++i) {
     if (entries_[i].view == view)
       return static_cast<int>(i);
   }
   return -1;
 }
 
 }  // namespace views