Adding a destination platform histogram for UMA.

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

Index: chrome/browser/chromeos/arc/intent_helper/arc_navigation_throttle.cc
diff --git a/chrome/browser/chromeos/arc/intent_helper/arc_navigation_throttle.cc b/chrome/browser/chromeos/arc/intent_helper/arc_navigation_throttle.cc
index f37ec9662af281cf761e8d9d467fc770b28efa74..eda220e9701d1fb27103841508ae83c2a6629bf4 100644
--- a/chrome/browser/chromeos/arc/intent_helper/arc_navigation_throttle.cc
+++ b/chrome/browser/chromeos/arc/intent_helper/arc_navigation_throttle.cc
@@ -373,6 +373,22 @@ void ArcNavigationThrottle::OnIntentPickerClosed(
   UMA_HISTOGRAM_ENUMERATION("Arc.IntentHandlerAction",
                             static_cast<int>(close_reason),
                             static_cast<int>(CloseReason::SIZE));
+
+  Platform platform = GetSelectedPlatform(selected_app_package, close_reason);
+  UMA_HISTOGRAM_ENUMERATION("Arc.IntentHandlerSelectedPlatform",
+                            static_cast<int>(platform),
+                            static_cast<int>(Platform::SIZE));
+}
+
+// static
+ArcNavigationThrottle::Platform ArcNavigationThrottle::GetSelectedPlatform(
+    const std::string& selected_app_package,
+    CloseReason close_reason) {
+  return (close_reason != CloseReason::ERROR &&
+          close_reason != CloseReason::DIALOG_DEACTIVATED &&
+          !ArcIntentHelperBridge::IsIntentHelperPackage(selected_app_package))
+             ? Platform::ARC
+             : Platform::CHROME;
 }
 
 // static