Notify launcher page with onTransitionChanged event

ui/app_list/views/contents_view.cc

Index: ui/app_list/views/contents_view.cc
diff --git a/ui/app_list/views/contents_view.cc b/ui/app_list/views/contents_view.cc
index c9ea27655c55962d62d45ed9a73f2db58491bcb9..e8efd76a0e0b96ccf18a56fc1f53063f4e6dd649 100644
--- a/ui/app_list/views/contents_view.cc
+++ b/ui/app_list/views/contents_view.cc
@@ -49,6 +49,8 @@ void ContentsView::Init(AppListModel* model,
                         AppListViewDelegate* view_delegate) {
   DCHECK(model);
 
+  view_delegate_ = view_delegate;
+
   if (app_list::switches::IsExperimentalAppListEnabled()) {
     std::vector<views::View*> custom_page_views =
         view_delegate->CreateCustomPageWebViews(GetLocalBounds().size());
@@ -56,7 +58,15 @@ void ContentsView::Init(AppListModel* model,
              custom_page_views.begin();
          it != custom_page_views.end();
          ++it) {
-      AddLauncherPage(*it, IDR_APP_LIST_NOTIFICATIONS_ICON);
+      // Only the first launcher page is considered to represent
+      // STATE_CUSTOM_LAUNCHER_PAGE.
+      if (it == custom_page_views.begin()) {
+        AddLauncherPage(*it,
+                        IDR_APP_LIST_NOTIFICATIONS_ICON,
+                        AppListModel::STATE_CUSTOM_LAUNCHER_PAGE);
+      } else {
+        AddLauncherPage(*it, IDR_APP_LIST_NOTIFICATIONS_ICON);
+      }
     }
 
     start_page_view_ = new StartPageView(app_list_main_view_, view_delegate);
@@ -211,6 +221,17 @@ gfx::Rect ContentsView::GetOffscreenPageBounds(int page_index) const {
   return bounds;
 }
 
+void ContentsView::NotifyCustomLauncherPageAnimationChanged(double progress,
+                                                            int current_page,
+                                                            int target_page) {
+  int custom_launcher_page_index =
+      GetPageIndexForState(AppListModel::STATE_CUSTOM_LAUNCHER_PAGE);
+  if (custom_launcher_page_index == target_page)
+    view_delegate_->CustomLauncherPageAnimationChanged(progress);
+  else if (custom_launcher_page_index == current_page)
+    view_delegate_->CustomLauncherPageAnimationChanged(1 - progress);
+}
+
 void ContentsView::UpdatePageBounds() {
   // The bounds calculations will potentially be mid-transition (depending on
   // the state of the PaginationModel).
@@ -226,6 +247,8 @@ void ContentsView::UpdatePageBounds() {
     }
   }
 
+  NotifyCustomLauncherPageAnimationChanged(progress, current_page, target_page);
+
   // Move |current_page| from 0 to its origin. Move |target_page| from its
   // origin to 0.
   gfx::Rect on_screen(GetDefaultContentsBounds());