mediaplayer: support dynamic playback rate

Bug: 19196501

Change-Id: I856b1507d5fa2cedfb645706d2435683a7d3e050
diff --git a/media/libmediaplayerservice/MediaPlayerService.cpp b/media/libmediaplayerservice/MediaPlayerService.cpp
index 694f1a4..0b18ae0 100644
--- a/media/libmediaplayerservice/MediaPlayerService.cpp
+++ b/media/libmediaplayerservice/MediaPlayerService.cpp
@@ -961,6 +961,14 @@
     return NO_ERROR;
 }
 
+status_t MediaPlayerService::Client::setPlaybackRate(float rate)
+{
+    ALOGV("[%d] setPlaybackRate(%f)", mConnId, rate);
+    sp<MediaPlayerBase> p = getPlayer();
+    if (p == 0) return UNKNOWN_ERROR;
+    return p->setPlaybackRate(rate);
+}
+
 status_t MediaPlayerService::Client::getCurrentPosition(int *msec)
 {
     ALOGV("getCurrentPosition");