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

components/startup_metric_utils/browser/startup_metric_host_impl.h

 // 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.
 
 #ifndef COMPONENTS_STARTUP_METRIC_UTILS_BROWSER_STARTUP_METRIC_HOST_IMPL_H_
 #define COMPONENTS_STARTUP_METRIC_UTILS_BROWSER_STARTUP_METRIC_HOST_IMPL_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "components/startup_metric_utils/common/startup_metric.mojom.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
 
 namespace startup_metric_utils {
 
 class StartupMetricHostImpl : public mojom::StartupMetricHost {
  public:
   static void Create(mojom::StartupMetricHostRequest request);
 
  private:
   explicit StartupMetricHostImpl(mojom::StartupMetricHostRequest request);
   ~StartupMetricHostImpl() override;
 
   void RecordRendererMainEntryTime(
-      const base::TimeTicks& renderer_main_entry_time) override;
+      base::TimeTicks renderer_main_entry_time) override;
 
   mojo::StrongBinding<mojom::StartupMetricHost> binding_;
 
   DISALLOW_COPY_AND_ASSIGN(StartupMetricHostImpl);
 };
 
 }  // namespace startup_metric_utils
 
 #endif  // COMPONENTS_STARTUP_METRIC_UTILS_BROWSER_STARTUP_METRIC_HOST_IMPL_H_