ScopedTrackers to help pin down where IOThread::InitSystemRequestContextOnIOThread is janky

net/spdy/spdy_session_pool.cc

Index: net/spdy/spdy_session_pool.cc
diff --git a/net/spdy/spdy_session_pool.cc b/net/spdy/spdy_session_pool.cc
index ddcc5744375d15dd04eb4aa0ca5c8d5b63870a83..a2d2ed607b5b8261ac3067f08a821a2af85d8827 100644
--- a/net/spdy/spdy_session_pool.cc
+++ b/net/spdy/spdy_session_pool.cc
@@ -6,6 +6,7 @@
 
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
+#include "base/profiler/scoped_tracker.h"
 #include "base/values.h"
 #include "net/base/address_list.h"
 #include "net/http/http_network_session.h"
@@ -64,6 +65,10 @@ SpdySessionPool::SpdySessionPool(
           HostPortPair::FromString(trusted_spdy_proxy)) {
   DCHECK(default_protocol_ >= kProtoSPDYMinimumVersion &&
          default_protocol_ <= kProtoSPDYMaximumVersion);
+  // TODO(michaeln): Remove ScopedTracker below once crbug.com/454983 is fixed
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "454983 SpdySessionPool::SpdySessionPool"));
   NetworkChangeNotifier::AddIPAddressObserver(this);
   if (ssl_config_service_.get())
     ssl_config_service_->AddObserver(this);