Adding instrumentation to locate the source of jankiness.

components/translate/core/browser/translate_script.cc

Index: components/translate/core/browser/translate_script.cc
diff --git a/components/translate/core/browser/translate_script.cc b/components/translate/core/browser/translate_script.cc
index a3c18eb15c5cfebfa15f5d30fb2ad7cc72c8e0eb..ff4288cbbbefb612468a01e8d17183e01da4c87e 100644
--- a/components/translate/core/browser/translate_script.cc
+++ b/components/translate/core/browser/translate_script.cc
@@ -8,6 +8,7 @@
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
+#include "base/profiler/scoped_profile.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
@@ -117,6 +118,11 @@ void TranslateScript::Request(const RequestCallback& callback) {
 
 void TranslateScript::OnScriptFetchComplete(
     int id, bool success, const std::string& data) {
+  // TODO(vadimt): Remove ScopedProfile below once crbug.com/422577 is fixed.
+  tracked_objects::ScopedProfile tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "422577 TranslateScript::OnScriptFetchComplete"));
+
   DCHECK_EQ(kFetcherId, id);
 
   scoped_ptr<const TranslateURLFetcher> delete_ptr(fetcher_.release());