base: Make ElapsedTimer movable

base/timer/elapsed_timer.cc

Index: base/timer/elapsed_timer.cc
diff --git a/base/timer/elapsed_timer.cc b/base/timer/elapsed_timer.cc
index f2a2f7113e8e4aa892fe7d507324ba2b6776d8ee..ca86ccd4da01e4bf596430896795f2bca94abb15 100644
--- a/base/timer/elapsed_timer.cc
+++ b/base/timer/elapsed_timer.cc
@@ -10,6 +10,14 @@ ElapsedTimer::ElapsedTimer() {
   begin_ = TimeTicks::Now();
 }
 
+ElapsedTimer::ElapsedTimer(ElapsedTimer&& other) {
+  begin_ = other.begin_;
+}
+
+void ElapsedTimer::operator=(ElapsedTimer&& other) {
+  begin_ = other.begin_;
+}
+
 TimeDelta ElapsedTimer::Elapsed() const {
   return TimeTicks::Now() - begin_;
 }