Address NewApi Android lint warnings in src/media.

media/base/android/java/src/org/chromium/media/WebAudioMediaCodecBridge.java

Index: media/base/android/java/src/org/chromium/media/WebAudioMediaCodecBridge.java
diff --git a/media/base/android/java/src/org/chromium/media/WebAudioMediaCodecBridge.java b/media/base/android/java/src/org/chromium/media/WebAudioMediaCodecBridge.java
index 128cee0e31778ab292f59e9a5298a19abd13f24e..257f69b5e6430ba3877f466d45d377d1f36c7521 100644
--- a/media/base/android/java/src/org/chromium/media/WebAudioMediaCodecBridge.java
+++ b/media/base/android/java/src/org/chromium/media/WebAudioMediaCodecBridge.java
@@ -4,11 +4,13 @@
 
 package org.chromium.media;
 
+import android.annotation.TargetApi;
 import android.content.Context;
 import android.media.MediaCodec;
 import android.media.MediaCodec.BufferInfo;
 import android.media.MediaExtractor;
 import android.media.MediaFormat;
+import android.os.Build;
 import android.os.ParcelFileDescriptor;
 import android.util.Log;
 
@@ -19,6 +21,8 @@ import java.io.File;
 import java.nio.ByteBuffer;
 
 @JNINamespace("media")
+//TODO: is this class only used on JELLY_BEAN and above?

[Raymond Toy, 2015/03/02 23:16:46]

Yes.  WebAudio requires the MediaCodec class that only exists on JellyBean and
later.  There is a check for this in content/child/runtime_features.cc so this
code is never run unless we're on JellyBean.

[newt (away), 2015/03/06 00:26:01]

Noted. Thanks.

+@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
 class WebAudioMediaCodecBridge {
     static final String LOG_TAG = "WebAudioMediaCodec";
     // TODO(rtoy): What is the correct timeout value for reading