Make UMA_HISTOGRAM_ENUMERATION work with scoped enums.

ash/common/shelf/shelf_view.h

 // Copyright (c) 2012 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 ASH_COMMON_SHELF_SHELF_VIEW_H_
 #define ASH_COMMON_SHELF_SHELF_VIEW_H_
 
 #include <memory>
 #include <string>
 #include <utility>
@@ skipping 36 matching lines @@
 class ShelfDelegate;
 class ShelfModel;
 struct ShelfItem;
 class ShelfWidget;
 class WmShelf;
 
 namespace test {
 class ShelfViewTestAPI;
 }
 
-extern const int SHELF_ALIGNMENT_UMA_ENUM_VALUE_BOTTOM;
-extern const int SHELF_ALIGNMENT_UMA_ENUM_VALUE_LEFT;
-extern const int SHELF_ALIGNMENT_UMA_ENUM_VALUE_RIGHT;
-extern const int SHELF_ALIGNMENT_UMA_ENUM_VALUE_COUNT;
+enum ShelfAlignmentUmaEnumValue {
+  SHELF_ALIGNMENT_UMA_ENUM_VALUE_BOTTOM,
+  SHELF_ALIGNMENT_UMA_ENUM_VALUE_LEFT,
+  SHELF_ALIGNMENT_UMA_ENUM_VALUE_RIGHT,
+  // Must be last entry in enum.
+  SHELF_ALIGNMENT_UMA_ENUM_VALUE_COUNT,
+};
 
 class ASH_EXPORT ShelfView : public views::View,
                              public ShelfModelObserver,
                              public InkDropButtonListener,
                              public views::ContextMenuController,
                              public views::FocusTraversable,
                              public views::BoundsAnimatorObserver,
                              public app_list::ApplicationDragAndDropHost {
  public:
   ShelfView(ShelfModel* model,
@@ skipping 394 matching lines @@
   ShelfButtonPressedMetricTracker shelf_button_pressed_metric_tracker_;
 
   base::WeakPtrFactory<ShelfView> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfView);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SHELF_SHELF_VIEW_H_