Switch GetWallClockTime to using vectors for input and output.

media/base/wall_clock_time_source.h

Index: media/base/wall_clock_time_source.h
diff --git a/media/base/wall_clock_time_source.h b/media/base/wall_clock_time_source.h
index 1de651889f45441640e52bed0d725ca4542c0564..22283192c39414b079589721438606c5dcf30fc6 100644
--- a/media/base/wall_clock_time_source.h
+++ b/media/base/wall_clock_time_source.h
@@ -7,13 +7,10 @@
 
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
+#include "base/time/default_tick_clock.h"
 #include "media/base/media_export.h"
 #include "media/base/time_source.h"
 
-namespace base {
-class TickClock;
-}
-
 namespace media {
 
 // A time source that uses interpolation based on the system clock.
@@ -28,14 +25,23 @@ class MEDIA_EXPORT WallClockTimeSource : public TimeSource {
   void SetPlaybackRate(double playback_rate) override;
   void SetMediaTime(base::TimeDelta time) override;
   base::TimeDelta CurrentMediaTime() override;
-  base::TimeTicks GetWallClockTime(base::TimeDelta time) override;
+  bool GetWallClockTimes(
+      const std::vector<base::TimeDelta>& media_timestamps,
+      std::vector<base::TimeTicks>* wall_clock_times) override;
 
-  void SetTickClockForTesting(scoped_ptr<base::TickClock> tick_clock);
+  void set_tick_clock_for_testing(base::TickClock* tick_clock) {
+    tick_clock_ = tick_clock;
+  }
 
  private:
   base::TimeDelta CurrentMediaTime_Locked();
 
-  scoped_ptr<base::TickClock> tick_clock_;
+  // Allow for an injectable tick clock for testing.
+  base::DefaultTickClock default_tick_clock_;
+
+  // If specified, used instead of |default_tick_clock_|.
+  base::TickClock* tick_clock_;
+
   bool ticking_;
 
   // While ticking we can interpolate the current media time by measuring the