Add Apps.AppListSearchResultDistanceFromOrigin UMA stat.

ui/app_list/views/search_result_container_view.h

 // Copyright (c) 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.
 
 #ifndef UI_APP_LIST_VIEWS_SEARCH_RESULT_CONTAINER_VIEW_H_
 #define UI_APP_LIST_VIEWS_SEARCH_RESULT_CONTAINER_VIEW_H_
 
 #include "base/memory/weak_ptr.h"
 #include "ui/app_list/app_list_model.h"
 #include "ui/views/view.h"
@@ skipping 25 matching lines @@
   int selected_index() const { return selected_index_; }
 
   // Returns whether |index| is a valid index for selection.
   bool IsValidSelectionIndex(int index) const;
 
   int num_results() const { return num_results_; }
 
   void set_container_score(double score) { container_score_ = score; }
   double container_score() const { return container_score_; }
 
+  // Notifies the container of the y-index of the first result of this container
+  // relative to all other result containers.
+  virtual void NotifyFirstResultYIndex(int y_index) = 0;

[Matt Giuca, 2015/05/11 06:50:40]

The documentation should say what this function *does*, not what its caller
does.

Also "relative to all other result containers" doesn't make sense; it is
absolute, not relative to any particular container.

How about:
// 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).

[calamity, 2015/05/11 07:15:03]

Done.

+
+  // 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;
   void ListItemMoved(size_t index, size_t target_index) override;
   void ListItemsChanged(size_t start, size_t count) override;
 
   // Updates the container for being selected. |from_bottom| is true if the view
   // was entered into from a selected view below it; false if entered into from
   // above. |directional_movement| is true if the navigation was caused by
   // directional controls (eg, arrow keys), as opposed to linear controls (eg,
@@ skipping 20 matching lines @@
 
   // The factory that consolidates multiple Update calls into one.
   base::WeakPtrFactory<SearchResultContainerView> update_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SearchResultContainerView);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_VIEWS_SEARCH_RESULT_CONTAINER_VIEW_H_