Introduces Android API level linting, fixes all current API lint errors.

webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioUtils.java

Index: webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioUtils.java
diff --git a/webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioUtils.java b/webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioUtils.java
index 9d7a600190c5151e689a75c8f4d156f2249ef2bd..45f564a4dd849491eb43a2bbb3af90e1a5361b6c 100644
--- a/webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioUtils.java
+++ b/webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioUtils.java
@@ -144,6 +144,11 @@ public final class WebRtcAudioUtils {
     return Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1;
   }
 
+  public static boolean runningOnJellyBeanMR2OrHigher() {
+    // July 24, 2013: Android 4.3. API Level 18.
+    return Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2;
+  }
+
   public static boolean runningOnLollipopOrHigher() {
     // API Level 21.
     return Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP;