Adding instrumentation to locate the source of jankiness.

content/browser/histogram_internals_request_job.cc

Index: content/browser/histogram_internals_request_job.cc
diff --git a/content/browser/histogram_internals_request_job.cc b/content/browser/histogram_internals_request_job.cc
index d8640dd1a70cf284c6d1b1ffbe5b243c9d160f90..0c4cf1d3bb2a695d3b37df1f8595c1c1db225fa0 100644
--- a/content/browser/histogram_internals_request_job.cc
+++ b/content/browser/histogram_internals_request_job.cc
@@ -6,6 +6,7 @@
 
 #include "base/metrics/histogram.h"
 #include "base/metrics/statistics_recorder.h"
+#include "base/profiler/scoped_profile.h"
 #include "content/browser/histogram_synchronizer.h"
 #include "net/base/escape.h"
 #include "net/base/net_errors.h"
@@ -59,6 +60,11 @@ int HistogramInternalsRequestJob::GetData(
     std::string* charset,
     std::string* data,
     const net::CompletionCallback& callback) const {
+  // TODO(vadimt): Remove ScopedProfile below once crbug.com/422489 is fixed.
+  tracked_objects::ScopedProfile tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "422489 HistogramInternalsRequestJob::GetData"));
+
   mime_type->assign("text/html");
   charset->assign("UTF8");