NuPlayerRenderer: prepareForMediaRenderingStart_l on en/disable offload audio

Bug: 22662910
Change-Id: I8fb4a9fce801295a4b251e27965aef048d217da6
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp b/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp
index 767417b..e9f3799 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp
+++ b/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp
@@ -1422,12 +1422,18 @@
     Mutex::Autolock autoLock(mLock);
     mFlags &= ~FLAG_OFFLOAD_AUDIO;
     ++mAudioDrainGeneration;
+    if (mAudioRenderingStartGeneration != -1) {
+        prepareForMediaRenderingStart_l();
+    }
 }
 
 void NuPlayer::Renderer::onEnableOffloadAudio() {
     Mutex::Autolock autoLock(mLock);
     mFlags |= FLAG_OFFLOAD_AUDIO;
     ++mAudioDrainGeneration;
+    if (mAudioRenderingStartGeneration != -1) {
+        prepareForMediaRenderingStart_l();
+    }
 }
 
 void NuPlayer::Renderer::onPause() {