Fixed experimental app list pagination indicator.

ui/app_list/views/contents_switcher_view.cc

 // Copyright 2014 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/contents_switcher_view.h"
 
 #include "ui/app_list/app_list_constants.h"
 #include "ui/app_list/views/contents_view.h"
 #include "ui/views/background.h"
 #include "ui/views/controls/button/custom_button.h"
@@ skipping 43 matching lines @@
         ui::ResourceBundle::GetSharedInstance().GetImageSkiaNamed(resource_id));
   }
   button->set_tag(page_index);
 
   // Add an indicator for the current launcher page.
   app_list::ContentsPageIndicatorView* indicator =
       new app_list::ContentsPageIndicatorView();
   indicator->set_background(
       views::Background::CreateSolidBackground(app_list::kPagerSelectedColor));
   indicator->SetVisible(false);
-  page_active_indicators_.push_back(indicator);
+  page_active_indicators_[page_index] = indicator;
 
   // A container view that will consume space when its child is not visible.
   // TODO(calamity): Remove this once BoxLayout supports space-consuming
   // invisible views.
   views::View* indicator_container = new views::View();
   indicator_container->SetLayoutManager(new views::FillLayout());
   indicator_container->AddChildView(indicator);
 
   // View containing the indicator view and image button.
   views::View* button_container = new views::View();
@@ skipping 10 matching lines @@
   contents_view_->SetActivePage(sender->tag());
 }
 
 void ContentsSwitcherView::TotalPagesChanged() {
 }
 
 void ContentsSwitcherView::SelectedPageChanged(int old_selected,
                                                int new_selected) {
   // Makes the indicator visible when it is first drawn and when the
   // selected page is changed.
-  int num_indicators = static_cast<int>(page_active_indicators_.size());
-  if (old_selected >= 0 && old_selected < num_indicators)
-    page_active_indicators_[old_selected]->SetVisible(false);
+  std::map<int, views::View*>::const_iterator it =
+      page_active_indicators_.find(old_selected);
+  if (it != page_active_indicators_.end())
+    it->second->SetVisible(false);
 
-  if (new_selected >= 0 && new_selected < num_indicators)
-    page_active_indicators_[new_selected]->SetVisible(true);
+  it = page_active_indicators_.find(new_selected);
+  if (it != page_active_indicators_.end())
+    it->second->SetVisible(true);
 }
 
 void ContentsSwitcherView::TransitionStarted() {
 }
 
 void ContentsSwitcherView::TransitionChanged() {
   // Change the indicator during a launcher page transition.
   const PaginationModel& pm = contents_view_->pagination_model();
   int old_selected = pm.selected_page();
   int new_selected = pm.transition().target_page;
   if (pm.IsRevertingCurrentTransition()) {
     // Swap the direction if the transition is reversed.
     old_selected = pm.transition().target_page;
     new_selected = pm.selected_page();
   }
 
   SelectedPageChanged(old_selected, new_selected);
 }
 
 }  // namespace app_list