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

chrome/browser/extensions/extension_gcm_app_handler_unittest.cc

Index: chrome/browser/extensions/extension_gcm_app_handler_unittest.cc
diff --git a/chrome/browser/extensions/extension_gcm_app_handler_unittest.cc b/chrome/browser/extensions/extension_gcm_app_handler_unittest.cc
index e5fd06b8b76e45dc0bda66c946abcde402c81a19..33b77aeb87c3be7de3c835d33eeaace32c3c3f4b 100644
--- a/chrome/browser/extensions/extension_gcm_app_handler_unittest.cc
+++ b/chrome/browser/extensions/extension_gcm_app_handler_unittest.cc
@@ -333,7 +333,8 @@ class ExtensionGCMAppHandlerTest : public testing::Test {
   }
 
   void UninstallExtension(const Extension* extension) {
-    extension_service_->UninstallExtension(extension->id(), false, NULL);
+    extension_service_->UninstallExtension(
+        extension->id(), ExtensionService::UNINSTALL_REASON_DEFAULT, NULL);
   }
 
   void SignIn(const std::string& username) {