Fix the Crash in the launcher's start page (a better approach).

ui/app_list/views/start_page_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/start_page_view.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/i18n/rtl.h"
@@ skipping 108 matching lines @@
 
   TileItemView* GetTileItemView(int index);
 
   const std::vector<SearchResultTileItemView*>& tile_views() const {
     return search_result_tile_views_;
   }
 
   AllAppsTileItemView* all_apps_button() { return all_apps_button_; }
 
   // Overridden from SearchResultContainerView:
-  int Update() override;
+  int DoUpdate() override;
   void UpdateSelectedIndex(int old_selected, int new_selected) override;
   void OnContainerSelected(bool from_bottom,
                            bool directional_movement) override;
   void NotifyFirstResultYIndex(int y_index) override;
   int GetYSize() override;
 
  private:
   void CreateAppsGrid(int apps_num);
 
   ContentsView* contents_view_;
@@ skipping 24 matching lines @@
 
 TileItemView* StartPageView::StartPageTilesContainer::GetTileItemView(
     int index) {
   DCHECK_GT(num_results(), index);
   if (index == num_results() - 1)
     return all_apps_button_;
 
   return search_result_tile_views_[index];
 }
 
-int StartPageView::StartPageTilesContainer::Update() {
+int StartPageView::StartPageTilesContainer::DoUpdate() {
   // Ignore updates and disable buttons when transitioning to a different
   // state.
   if (contents_view_->GetActiveState() != AppListModel::STATE_START) {
     for (auto* view : search_result_tile_views_)
       view->SetEnabled(false);
 
     return num_results();
   }
 
   std::vector<SearchResult*> display_results =
@@ skipping 19 matching lines @@
 
   Layout();
   parent()->Layout();
   // Add 1 to the results size to account for the all apps button.
   return display_results.size() + 1;
 }
 
 void StartPageView::StartPageTilesContainer::UpdateSelectedIndex(
     int old_selected,
     int new_selected) {
-  if (old_selected >= 0)
+  if (old_selected >= 0 && old_selected < num_results())
     GetTileItemView(old_selected)->SetSelected(false);
 
-  if (new_selected >= 0)
+  if (new_selected >= 0 && new_selected < num_results())
     GetTileItemView(new_selected)->SetSelected(true);
 }
 
 void StartPageView::StartPageTilesContainer::OnContainerSelected(
     bool /*from_bottom*/,
     bool /*directional_movement*/) {
   NOTREACHED();
 }
 
 void StartPageView::StartPageTilesContainer::NotifyFirstResultYIndex(
@@ skipping 125 matching lines @@
 
 void StartPageView::OnShown() {
   // When the start page is shown, show or hide the custom launcher page
   // based on whether it is enabled.
   CustomLauncherPageView* custom_page_view =
       app_list_main_view_->contents_view()->custom_page_view();
   if (custom_page_view) {
     custom_page_view->SetVisible(
         app_list_main_view_->ShouldShowCustomLauncherPage());
   }
+  tiles_container_->ClearSelectedIndex();
   tiles_container_->Update();
-  tiles_container_->ClearSelectedIndex();
   custom_launcher_page_background_->SetSelected(false);
 }
 
 gfx::Rect StartPageView::GetPageBoundsForState(
     AppListModel::State state) const {
   gfx::Rect onscreen_bounds(GetFullContentsBounds());
   if (state == AppListModel::STATE_START)
     return onscreen_bounds;
 
   return GetAboveContentsOffscreenBounds(onscreen_bounds.size());
@@ skipping 152 matching lines @@
   // is enabled).
   if (event->type() == ui::ET_SCROLL && event->y_offset() < 0)
     MaybeOpenCustomLauncherPage();
 }
 
 TileItemView* StartPageView::GetTileItemView(size_t index) {
   return tiles_container_->GetTileItemView(index);
 }
 
 }  // namespace app_list