[Mac] Reduce timer CPU use in MessagePumpCFRunLoopBase.

base/message_loop/message_pump_mac.h

 // 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.
 
 // The basis for all native run loops on the Mac is the CFRunLoop.  It can be
 // used directly, it can be used as the driving force behind the similar
 // Foundation NSRunLoop, and it can be used to implement higher-level event
 // loops such as the NSApplication event loop.
 //
 // This file introduces a basic CFRunLoop-based implementation of the
@@ skipping 63 matching lines @@
 // AutoreleasePoolType* instead.
 #if !defined(__OBJC__) || __has_feature(objc_arc)
 class AutoreleasePoolType;
 #else   // !defined(__OBJC__) || __has_feature(objc_arc)
 typedef NSAutoreleasePool AutoreleasePoolType;
 #endif  // !defined(__OBJC__) || __has_feature(objc_arc)
 
 class MessagePumpCFRunLoopBase : public MessagePump {
   // Needs access to CreateAutoreleasePool.
   friend class MessagePumpScopedAutoreleasePool;
+  friend class TestMessagePumpCFRunLoopBase;
+
  public:
   MessagePumpCFRunLoopBase();
   ~MessagePumpCFRunLoopBase() override;
 
   // Subclasses should implement the work they need to do in MessagePump::Run
   // in the DoRun method.  MessagePumpCFRunLoopBase::Run calls DoRun directly.
   // This arrangement is used because MessagePumpCFRunLoopBase needs to set
   // up and tear down things before and after the "meat" of DoRun.
   void Run(Delegate* delegate) override;
   virtual void DoRun(Delegate* delegate) = 0;
@@ skipping 93 matching lines @@
   Delegate* delegate_;
 
   // The time that delayed_work_timer_ is scheduled to fire.  This is tracked
   // independently of CFRunLoopTimerGetNextFireDate(delayed_work_timer_)
   // to be able to reset the timer properly after waking from system sleep.
   // See PowerStateNotification.
   CFAbsoluteTime delayed_work_fire_time_;
 
   base::TimerSlack timer_slack_;
 
+  // True if private API for validating/invalidating CFRunLoopTimers is
+  // available for use.
+  bool can_invalidate_timers_;
+
   // The recursion depth of the currently-executing CFRunLoopRun loop on the
   // run loop's thread.  0 if no run loops are running inside of whatever scope
   // the object was created in.
   int nesting_level_;
 
   // The recursion depth (calculated in the same way as nesting_level_) of the
   // innermost executing CFRunLoopRun loop started by a call to Run.
   int run_nesting_level_;
 
   // The deepest (numerically highest) recursion depth encountered since the
@@ skipping 138 matching lines @@
   DISALLOW_IMPLICIT_CONSTRUCTORS(MessagePumpMac);
 };
 
 // Tasks posted to the message loop are posted under this mode, as well
 // as kCFRunLoopCommonModes.
 extern const CFStringRef BASE_EXPORT kMessageLoopExclusiveRunLoopMode;
 
 }  // namespace base
 
 #endif  // BASE_MESSAGE_LOOP_MESSAGE_PUMP_MAC_H_