Replace "external_install" boolean parameter with explicit enumeration in ExtensionUninstall method.

chrome/browser/ui/webui/ntp/app_launcher_handler.cc

Index: chrome/browser/ui/webui/ntp/app_launcher_handler.cc
diff --git a/chrome/browser/ui/webui/ntp/app_launcher_handler.cc b/chrome/browser/ui/webui/ntp/app_launcher_handler.cc
index 17a710d32c6ac7b2e6eb29c9a8da09e2a5270de6..064c8da8ed10c003bae5920ba6a34904d0e801a5 100644
--- a/chrome/browser/ui/webui/ntp/app_launcher_handler.cc
+++ b/chrome/browser/ui/webui/ntp/app_launcher_handler.cc
@@ -808,8 +808,10 @@ void AppLauncherHandler::ExtensionUninstallAccepted() {
   if (!extension)
     return;
 
-  extension_service_->UninstallExtension(extension_id_prompting_,
-                                         false /* external_uninstall */, NULL);
+  extension_service_->UninstallExtension(
+      extension_id_prompting_,
+      ExtensionService::kUninstallReasonUserInitiated,
+      NULL);
   CleanupAfterUninstall();
 }