Add Apps.AppListSearchResultDistanceFromOrigin UMA stat.

ui/app_list/views/search_result_container_view.h

Index: ui/app_list/views/search_result_container_view.h
diff --git a/ui/app_list/views/search_result_container_view.h b/ui/app_list/views/search_result_container_view.h
index c2fafe326966ced80ca319021c10b3bb70c49b69..14f7e2c36ccf51676a712879360c94d5ba388017 100644
--- a/ui/app_list/views/search_result_container_view.h
+++ b/ui/app_list/views/search_result_container_view.h
@@ -43,10 +43,22 @@ class APP_LIST_EXPORT SearchResultContainerView : public views::View,
   void set_container_score(double score) { container_score_ = score; }
   double container_score() const { return container_score_; }
 
+  // Updates the distance_from_origin() properties of the results in this
+  // container. |y_index| is the absolute y-index of the first result of this
+  // container (counting from the top of the app list).
+  virtual void NotifyFirstResultYIndex(int y_index) = 0;
+
+  // Gets the number of down keystrokes from the beginning to the end of this
+  // container.
+  virtual int GetYSize() = 0;
+
   // Schedules an Update call using |update_factory_|. Do nothing if there is a
   // pending call.
   void ScheduleUpdate();
 
+  // Returns whether an update is currently scheduled for this container.
+  bool UpdateScheduled();
+
   // Overridden from ui::ListModelObserver:
   void ListItemsAdded(size_t start, size_t count) override;
   void ListItemsRemoved(size_t start, size_t count) override;