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      1 // Copyright 2014 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CHROME_BROWSER_MAC_MAC_STARTUP_PROFILER_H_
      6 #define CHROME_BROWSER_MAC_MAC_STARTUP_PROFILER_H_
      7 
      8 #include <map>
      9 
     10 #include "base/memory/singleton.h"
     11 #include "base/time/time.h"
     12 
     13 // A lightweight profiler of startup performance. Records UMA metrics for the
     14 // time delta between Chrome's launch and major initialization phases.
     15 class MacStartupProfiler {
     16  public:
     17   // Returns pointer to the singleton instance for the current process.
     18   static MacStartupProfiler* GetInstance();
     19 
     20   MacStartupProfiler();
     21   ~MacStartupProfiler();
     22 
     23   // These locations correspond to major phases of Chrome startup.
     24   // Profiling of these locations should occur at the beginning of the method
     25   // indicated by the enum name.
     26   // The ordering of the enum matches the order in which the initialization
     27   // phases are reached.
     28   enum Location {
     29     PRE_MAIN_MESSAGE_LOOP_START,
     30     AWAKE_FROM_NIB,
     31     POST_MAIN_MESSAGE_LOOP_START,
     32     PRE_PROFILE_INIT,
     33     POST_PROFILE_INIT,
     34     WILL_FINISH_LAUNCHING,
     35     DID_FINISH_LAUNCHING,
     36   };
     37 
     38   // Record timestamp for the given location event.
     39   void Profile(Location location);
     40 
     41   // Call once to record all UMA metrics for all profiled locations.
     42   void RecordMetrics();
     43 
     44  private:
     45   friend struct DefaultSingletonTraits<MacStartupProfiler>;
     46 
     47   // Returns the name of the histogram for the given location.
     48   const std::string HistogramName(Location location);
     49 
     50   // Records UMA metrics for a specific location.
     51   void RecordHistogram(Location location, const base::TimeDelta& delta);
     52 
     53   // Keeps track of the time at which each initialization phase was reached.
     54   std::map<Location, base::Time> profiled_times_;
     55 
     56   // Whether UMA metrics have been recorded. Only record UMA metrics once.
     57   bool recorded_metrics_;
     58 
     59   DISALLOW_COPY_AND_ASSIGN(MacStartupProfiler);
     60 };
     61 
     62 #endif  // CHROME_BROWSER_MAC_MAC_STARTUP_PROFILER_H_
     63