Switch to double for time calculations using playback rate.

chromecast/media/base/switching_media_renderer.h

Index: chromecast/media/base/switching_media_renderer.h
diff --git a/chromecast/media/base/switching_media_renderer.h b/chromecast/media/base/switching_media_renderer.h
index 830cef671e0c22587850b1d32c7fdc6d09543b94..436a1dc167451b23e9fed3f828c56a71b6c695fa 100644
--- a/chromecast/media/base/switching_media_renderer.h
+++ b/chromecast/media/base/switching_media_renderer.h
@@ -44,7 +44,7 @@ class SwitchingMediaRenderer : public ::media::Renderer {
               const ::media::CdmAttachedCB& cdm_attached_cb) override;
   void Flush(const base::Closure& flush_cb) override;
   void StartPlayingFrom(base::TimeDelta time) override;
-  void SetPlaybackRate(float playback_rate) override;
+  void SetPlaybackRate(double playback_rate) override;
   void SetVolume(float volume) override;
   base::TimeDelta GetMediaTime() override;
   bool HasAudio() override;