Added Launcher_SwitchTask UMA user action.

ash/shelf/shelf_view.h

Index: ash/shelf/shelf_view.h
diff --git a/ash/shelf/shelf_view.h b/ash/shelf/shelf_view.h
index 037922e55b09f33bbc21ff9fbd33c57a39087aed..56dd95bc551325ed20b05504418f47c3a1d0b92d 100644
--- a/ash/shelf/shelf_view.h
+++ b/ash/shelf/shelf_view.h
@@ -5,10 +5,12 @@
 #ifndef ASH_SHELF_SHELF_VIEW_H_
 #define ASH_SHELF_SHELF_VIEW_H_
 
+#include <string>
 #include <utility>
 #include <vector>
 
 #include "ash/shelf/shelf_button_host.h"
+#include "ash/shelf/shelf_item_delegate.h"
 #include "ash/shelf/shelf_model_observer.h"
 #include "ash/wm/gestures/shelf_gesture_handler.h"
 #include "base/observer_list.h"
@@ -276,6 +278,13 @@ class ASH_EXPORT ShelfView : public views::View,
   // Overridden from views::ButtonListener:
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
+  // Records UMA statistics for the input source when an icon was activated.
+  void RecordIconActivatedSource(const ui::Event& event);
+
+  // Records UMA statistics for the action performed by activating an icon.
+  void RecordIconActivatedAction(
+      ShelfItemDelegate::PerformedAction performed_action);
+
   // Show the list of all running items for this |item|. It will return true
   // when the menu was shown and false if there were no possible items to
   // choose from. |source| specifies the view which is responsible for showing