Update mojo typemaps for base::Time* to pass by value.

components/startup_metric_utils/browser/startup_metric_host_impl.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/startup_metric_utils/browser/startup_metric_host_impl.h"
 
 #include "components/startup_metric_utils/browser/startup_metric_utils.h"
 
 namespace startup_metric_utils {
 // static
 void StartupMetricHostImpl::Create(mojom::StartupMetricHostRequest request) {
   new StartupMetricHostImpl(std::move(request));
 }
 
 StartupMetricHostImpl::StartupMetricHostImpl(
     mojom::StartupMetricHostRequest request)
     : binding_(this, std::move(request)) {}
 
 StartupMetricHostImpl::~StartupMetricHostImpl() = default;
 
 void StartupMetricHostImpl::RecordRendererMainEntryTime(
-    const base::TimeTicks& renderer_main_entry_time) {
+    base::TimeTicks renderer_main_entry_time) {
   startup_metric_utils::RecordRendererMainEntryTime(renderer_main_entry_time);
 }
 
 }  // namespace startup_metric_utils