Use TimeTicks as much as possible in startup_metric_utils.

mojo/services/tracing/tracing_app.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 MOJO_SERVICES_TRACING_TRACING_APP_H_
 #define MOJO_SERVICES_TRACING_TRACING_APP_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
@@ skipping 33 matching lines @@
       mojo::InterfaceRequest<StartupPerformanceDataCollector> request) override;
 
   // tracing::TraceCollector implementation.
   void Start(mojo::ScopedDataPipeProducerHandle stream,
              const mojo::String& categories) override;
   void StopAndFlush() override;
 
   // StartupPerformanceDataCollector implementation.
   void SetShellProcessCreationTime(int64 time) override;
   void SetShellMainEntryPointTime(int64 time) override;
-  void SetBrowserMessageLoopStartTime(int64 time) override;
-  void SetBrowserWindowDisplayTime(int64 time) override;
+  void SetBrowserMessageLoopStartTicks(int64 ticks) override;
+  void SetBrowserWindowDisplayTicks(int64 ticks) override;
   void SetBrowserOpenTabsTimeDelta(int64 delta) override;
-  void SetFirstWebContentsMainFrameLoadTime(int64 time) override;
-  void SetFirstVisuallyNonEmptyLayoutTime(int64 time) override;
+  void SetFirstWebContentsMainFrameLoadTicks(int64 ticks) override;
+  void SetFirstVisuallyNonEmptyLayoutTicks(int64 ticks) override;
   void GetStartupPerformanceTimes(
       const GetStartupPerformanceTimesCallback& callback) override;
 
   void AllDataCollected();
 
   scoped_ptr<TraceDataSink> sink_;
   ScopedVector<TraceRecorderImpl> recorder_impls_;
   mojo::WeakInterfacePtrSet<TraceProvider> provider_ptrs_;
   mojo::Binding<TraceCollector> collector_binding_;
   mojo::WeakBindingSet<StartupPerformanceDataCollector>
       startup_performance_data_collector_bindings_;
   StartupPerformanceTimes startup_performance_times_;
   bool tracing_active_;
   mojo::String tracing_categories_;
 
   DISALLOW_COPY_AND_ASSIGN(TracingApp);
 };
 
 }  // namespace tracing
 
 #endif  // MOJO_SERVICES_TRACING_TRACING_APP_H_