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

talk/app/webrtc/java/src/org/webrtc/MediaCodecVideoEncoder.java

Index: talk/app/webrtc/java/src/org/webrtc/MediaCodecVideoEncoder.java
diff --git a/talk/app/webrtc/java/src/org/webrtc/MediaCodecVideoEncoder.java b/talk/app/webrtc/java/src/org/webrtc/MediaCodecVideoEncoder.java
index 988d62a3ff4622786aad0c1ab37ca6384324d93a..2f7d48e6f8ee2ce28d8d0b47168007eeb99e0341 100644
--- a/talk/app/webrtc/java/src/org/webrtc/MediaCodecVideoEncoder.java
+++ b/talk/app/webrtc/java/src/org/webrtc/MediaCodecVideoEncoder.java
@@ -27,6 +27,7 @@
 
 package org.webrtc;
 
+import android.annotation.TargetApi;
 import android.media.MediaCodec;
 import android.media.MediaCodecInfo.CodecCapabilities;
 import android.media.MediaCodecInfo;
@@ -44,6 +45,8 @@ import java.util.concurrent.CountDownLatch;
 
 // Java-side of peerconnection_jni.cc:MediaCodecVideoEncoder.
 // This class is an implementation detail of the Java PeerConnection API.
+@TargetApi(19)
+@SuppressWarnings("deprecation")
 public class MediaCodecVideoEncoder {
   // This class is constructed, operated, and destroyed by its C++ incarnation,
   // so the class and its methods have non-public visibility.  The API this