Simplify base::Timer implementation

base/timer/timer.cc

 // Copyright (c) 2012 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 "base/timer/timer.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 45 matching lines @@
   // The task remains in the MessageLoop queue, but nothing will happen when it
   // runs.
   void Abandon() {
     timer_ = NULL;
   }
 
  private:
   Timer* timer_;
 };
 
-Timer::Timer(bool retain_user_task, bool is_repeating)
-    : Timer(retain_user_task, is_repeating, nullptr) {}
-
 Timer::Timer(bool retain_user_task, bool is_repeating, TickClock* tick_clock)
     : scheduled_task_(nullptr),
       thread_id_(0),
       is_repeating_(is_repeating),
       retain_user_task_(retain_user_task),
       tick_clock_(tick_clock),
       is_running_(false) {}
 
 Timer::Timer(const tracked_objects::Location& posted_from,
              TimeDelta delay,
              const base::Closure& user_task,
-             bool is_repeating)
-    : Timer(posted_from, delay, user_task, is_repeating, nullptr) {}
-
-Timer::Timer(const tracked_objects::Location& posted_from,
-             TimeDelta delay,
-             const base::Closure& user_task,
              bool is_repeating,
              TickClock* tick_clock)
     : scheduled_task_(nullptr),
       posted_from_(posted_from),
       delay_(delay),
       user_task_(user_task),
       thread_id_(0),
       is_repeating_(is_repeating),
       retain_user_task_(true),
       tick_clock_(tick_clock),
@@ skipping 132 matching lines @@
     PostNewScheduledTask(delay_);
   else
     Stop();
 
   task.Run();
 
   // No more member accesses here: *this could be deleted at this point.
 }
 
 }  // namespace base