Refactor app list ContentsView to use page indices, not show states.

ui/app_list/views/app_list_main_view.cc

 // Copyright 2013 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/app_list/views/app_list_main_view.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 152 matching lines @@
 void AppListMainView::ModelChanged() {
   pending_icon_loaders_.clear();
   model_ = delegate_->GetModel();
   search_box_view_->ModelChanged();
   delete contents_view_;
   contents_view_ = NULL;
   AddContentsView();
   Layout();
 }
 
-void AppListMainView::OnContentsViewShowStateChanged() {
-  search_box_view_->SetVisible(contents_view_->show_state() !=
-                               ContentsView::SHOW_START_PAGE);
+void AppListMainView::OnContentsViewActivePageChanged() {
+  search_box_view_->SetVisible(
+      !contents_view_->IsNamedPageActive(ContentsView::SHOW_START_PAGE));
 }
 
 void AppListMainView::OnStartPageSearchButtonPressed() {
   search_box_view_->SetVisible(true);
   search_box_view_->search_box()->SetText(base::string16());
   search_box_view_->RequestFocus();
 }
 
 void AppListMainView::SetDragAndDropHostOfCurrentAppList(
     ApplicationDragAndDropHost* drag_and_drop_host) {
@@ skipping 99 matching lines @@
   // Resubmit the query via a posted task so that all observers for the
   // uninstall notification are notified.
   base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&AppListMainView::QueryChanged,
                  weak_ptr_factory_.GetWeakPtr(),
                  search_box_view_));
 }
 
 }  // namespace app_list