Remove unnecessary instrumentation for several jank bugs.

net/http/disk_based_cert_cache.cc

Index: net/http/disk_based_cert_cache.cc
diff --git a/net/http/disk_based_cert_cache.cc b/net/http/disk_based_cert_cache.cc
index b91fb10bc44a23b643cae67db13a1a0152967f77..9b39d85264cc24c5d54b468a3fe0122362da0cda 100644
--- a/net/http/disk_based_cert_cache.cc
+++ b/net/http/disk_based_cert_cache.cc
@@ -10,7 +10,6 @@
 #include "base/callback_helpers.h"
 #include "base/memory/ref_counted.h"
 #include "base/metrics/histogram.h"
-#include "base/profiler/scoped_tracker.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "net/base/io_buffer.h"
@@ -398,11 +397,6 @@ void DiskBasedCertCache::ReadWorker::Cancel() {
 }
 
 void DiskBasedCertCache::ReadWorker::OnIOComplete(int rv) {
-  // TODO(vadimt): Remove ScopedTracker below once crbug.com/422516 is fixed.
-  tracked_objects::ScopedTracker tracking_profile(
-      FROM_HERE_WITH_EXPLICIT_FUNCTION(
-          "422516 DiskBasedCertCache::ReadWorker::OnIOComplete"));
-
   if (canceled_) {
     Finish(ERR_FAILED);
     return;