Temporary hack to fix telemetry_perf_unittests flakes.

components/metrics/metrics_state_manager.cc

Index: components/metrics/metrics_state_manager.cc
diff --git a/components/metrics/metrics_state_manager.cc b/components/metrics/metrics_state_manager.cc
index cf1b4a126abd6af56515dfd07f84d84c1fbf01bf..b470e3db1e6cbc1a8a473b6628a16a74b6d2adff 100644
--- a/components/metrics/metrics_state_manager.cc
+++ b/components/metrics/metrics_state_manager.cc
@@ -257,7 +257,11 @@ MetricsStateManager::LoadClientInfoAndMaybeMigrate() {
 
   // The GUID retrieved (and possibly fixed above) should be valid unless
   // retrieval failed.
-  DCHECK(!client_info || base::IsValidGUID(client_info->client_id));
+  // DCHECK(!client_info || base::IsValidGUID(client_info->client_id));
+  // Temporary hack for http://crbug.com/635255.
+  // TODO(asvitkine): address this the right way.
+  if (client_info && !base::IsValidGUID(client_info->client_id))
+    return nullptr;
 
   return client_info;
 }