Expose Timer::AbandonAndStop, so it can safely be destroyed on another thread.

base/timer/timer.cc

Index: base/timer/timer.cc
diff --git a/base/timer/timer.cc b/base/timer/timer.cc
index 1f6efcc7e3db704b60f2740f36e92b277734f1fd..6a64b9d357b4c0421dc2640236e4b0d56c682ebc 100644
--- a/base/timer/timer.cc
+++ b/base/timer/timer.cc
@@ -32,7 +32,7 @@ class BaseTimerTaskInternal {
     // destructed.  If so, don't leave Timer with a dangling pointer
     // to this.
     if (timer_)
-      timer_->AbandonAndStop();
+      timer_->Stop();
   }
 
   void Run() {
@@ -100,7 +100,7 @@ Timer::Timer(const tracked_objects::Location& posted_from,
 
 Timer::~Timer() {
   DCHECK(origin_sequence_checker_.CalledOnValidSequence());
-  AbandonAndStop();
+  Stop();
 }
 
 bool Timer::IsRunning() const {
@@ -142,6 +142,7 @@ void Timer::Stop() {
   // RunScheduledTask(): https://crbug.com/587199.
   // DCHECK(origin_sequence_checker_.CalledOnValidSequence());
 
+  AbandonScheduledTask();
   is_running_ = false;
 
   // It's safe to destroy or restart Timer on another sequence after Stop().