Adding instrumentation to locate the source of jankiness.

components/signin/core/browser/mutable_profile_oauth2_token_service.cc

Index: components/signin/core/browser/mutable_profile_oauth2_token_service.cc
diff --git a/components/signin/core/browser/mutable_profile_oauth2_token_service.cc b/components/signin/core/browser/mutable_profile_oauth2_token_service.cc
index 768a75a2dd7eaeffdc68381af8e1f55bbeda8fd8..7bd421c0023f88abe0c4732c2349607bf261579b 100644
--- a/components/signin/core/browser/mutable_profile_oauth2_token_service.cc
+++ b/components/signin/core/browser/mutable_profile_oauth2_token_service.cc
@@ -4,6 +4,7 @@
 
 #include "components/signin/core/browser/mutable_profile_oauth2_token_service.h"
 
+#include "base/profiler/scoped_profile.h"
 #include "components/signin/core/browser/signin_client.h"
 #include "components/signin/core/browser/signin_metrics.h"
 #include "components/signin/core/browser/webdata/token_web_data.h"
@@ -184,6 +185,11 @@ void MutableProfileOAuth2TokenService::LoadCredentials(
 void MutableProfileOAuth2TokenService::OnWebDataServiceRequestDone(
     WebDataServiceBase::Handle handle,
     const WDTypedResult* result) {
+  // TODO(vadimt): Remove ScopedProfile below once crbug.com/422460 is fixed.
+  tracked_objects::ScopedProfile tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "422460 MutableProfileOAuth2Token...::OnWebDataServiceRequestDone"));
+
   DCHECK_EQ(web_data_service_request_, handle);
   web_data_service_request_ = 0;