Enable platform echo cancellation through the AudioRecord path.

media/audio/android/audio_record_input.h

Index: media/audio/android/audio_record_input.h
diff --git a/media/audio/android/audio_record_input.h b/media/audio/android/audio_record_input.h
index 3a95d51180e6421e693ba2d284d5a5e392470fcb..0a2578b107937595ca4820c151af80e1ec12cb7c 100644
--- a/media/audio/android/audio_record_input.h
+++ b/media/audio/android/audio_record_input.h
@@ -19,6 +19,9 @@ class AudioManagerAndroid;
 // AudioRecordInput.java. This class is created and lives on the Audio Manager
 // thread but recorded audio buffers are delivered on a thread managed by
 // the Java class.
+//
+// The Java class makes use of AudioEffect features which are first available
+// in Jelly Bean. It should not be instantiated running against earlier SDKs.
 class MEDIA_EXPORT AudioRecordInputStream : public AudioInputStream {
  public:
   AudioRecordInputStream(AudioManagerAndroid* manager,