Adding a destination platform histogram for UMA.

chrome/browser/chromeos/arc/intent_helper/arc_navigation_throttle.h

Index: chrome/browser/chromeos/arc/intent_helper/arc_navigation_throttle.h
diff --git a/chrome/browser/chromeos/arc/intent_helper/arc_navigation_throttle.h b/chrome/browser/chromeos/arc/intent_helper/arc_navigation_throttle.h
index 0c7cf3e80e3819f12dc9b424102db64f90af7606..7747b2ad11b709c41f89bfeb0c2482049f6e39f3 100644
--- a/chrome/browser/chromeos/arc/intent_helper/arc_navigation_throttle.h
+++ b/chrome/browser/chromeos/arc/intent_helper/arc_navigation_throttle.h
@@ -43,6 +43,12 @@ class ArcNavigationThrottle : public content::NavigationThrottle {
     INVALID = SIZE,
   };
 
+  enum class Platform : int {
+    ARC = 0,
+    CHROME = 1,
+    SIZE,
+  };
+
   // Restricts the amount of apps displayed to the user without the need of a
   // ScrollView.
   enum { kMaxAppResults = 3 };
@@ -79,6 +85,8 @@ class ArcNavigationThrottle : public content::NavigationThrottle {
   static bool IsSwapElementsNeededForTesting(
       const mojo::Array<mojom::IntentHandlerInfoPtr>& handlers,
       std::pair<size_t, size_t>* out_indices);
+  static Platform GetSelectedPlatform(const std::string& selected_app_package,
+                                      CloseReason close_reason);
 
  private:
   // content::Navigation implementation: