Android: Fix warnings

TBR=sakal@webrtc.org

Bug: webrtc:6597,webrtc:8534
Change-Id: I39f96d9e0e6d604051b1cc13368dd44fc82b30b0
Reviewed-on: https://webrtc-review.googlesource.com/23622
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Commit-Queue: Magnus Jedvert <magjed@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20719}
diff --git a/sdk/android/api/org/webrtc/RtpParameters.java b/sdk/android/api/org/webrtc/RtpParameters.java
index fde2b35..f1cca9d 100644
--- a/sdk/android/api/org/webrtc/RtpParameters.java
+++ b/sdk/android/api/org/webrtc/RtpParameters.java
@@ -10,7 +10,8 @@
 
 package org.webrtc;
 
-import java.util.LinkedList;
+import java.util.List;
+import java.util.ArrayList;
 
 /**
  * The parameters for an {@code RtpSender}, as defined in
@@ -48,14 +49,9 @@
     public Integer numChannels;
   }
 
-  public final LinkedList<Encoding> encodings;
+  public final List<Encoding> encodings = new ArrayList<>();
   // Codec parameters can't currently be changed between getParameters and
   // setParameters. Though in the future it will be possible to reorder them or
   // remove them.
-  public final LinkedList<Codec> codecs;
-
-  public RtpParameters() {
-    encodings = new LinkedList<Encoding>();
-    codecs = new LinkedList<Codec>();
-  }
+  public final List<Codec> codecs = new ArrayList<>();
 }