Eliminate dependencies on hardware/audio.h (trivial cases)

frameworks/av must not depend on hardware/ (except for the code
from libaudiohal that actually calls into HAL).

This CL deals with simple cases where depending on system/audio.h
is enough.

Change-Id: Ia2cb66cc8c92316ce5ab884a008d5e531263c2e4
Test: make
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 3b05c48..02e8522 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -33,13 +33,13 @@
 #include <utils/Trace.h>
 
 #include <private/media/AudioTrackShared.h>
-#include <hardware/audio.h>
 #include <audio_effects/effect_ns.h>
 #include <audio_effects/effect_aec.h>
 #include <audio_utils/conversion.h>
 #include <audio_utils/primitives.h>
 #include <audio_utils/format.h>
 #include <audio_utils/minifloat.h>
+#include <system/audio.h>
 
 // NBAIO implementations
 #include <media/nbaio/AudioStreamInSource.h>
@@ -2750,9 +2750,7 @@
             ALOG_ASSERT(mCallbackThread != 0);
             mCallbackThread->setDraining(mDrainSequence);
         }
-        status_t result = mOutput->stream->drain(
-            (mMixerStatus == MIXER_DRAIN_TRACK) ? AUDIO_DRAIN_EARLY_NOTIFY
-                                                : AUDIO_DRAIN_ALL);
+        status_t result = mOutput->stream->drain(mMixerStatus == MIXER_DRAIN_TRACK);
         ALOGE_IF(result != OK, "Error when draining stream: %d", result);
     }
 }