Remove redundant field initialization in Java code.

chrome/android/java/src/org/chromium/chrome/browser/media/router/cast/CastMessageHandler.java

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.media.router.cast;
 
 import android.os.Handler;
 import android.support.v4.util.ArrayMap;
 import android.util.SparseArray;
 
-import org.chromium.base.Log;
-import org.chromium.base.VisibleForTesting;
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
+import org.chromium.base.Log;
+import org.chromium.base.VisibleForTesting;
+
 import java.util.ArrayDeque;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Queue;
 
 /**
  * The handler for cast messages. It receives events between the Cast SDK and the page, process and
  * dispatch the messages accordingly. The handler talks to the Cast SDK via CastSession, and
@@ skipping 38 matching lines @@
     // expect them to be named FOO. The reason being that FOO might exist in multiple namespaces
     // but the client isn't aware of namespacing.
     private static Map<String, String> sMediaOverloadedMessageTypes;
 
     private SparseArray<RequestRecord> mRequests;
     private ArrayMap<String, Queue<Integer>> mStopRequests;
     private Queue<RequestRecord> mVolumeRequests;
 
     // The reference to CastSession, only valid after calling {@link onSessionCreated}, and will be
     // reset to null when calling {@link onApplicationStopped}.
-    private CastSession mSession = null;
+    private CastSession mSession;
     private final CastMediaRouteProvider mRouteProvider;
     private Handler mHandler;
 
     /**
      * The record for client requests. {@link CastMessageHandler} uses this class to manage the
      * client requests and match responses to the requests.
      */
     static class RequestRecord {
         public final String clientId;
         public final int sequenceNumber;
@@ skipping 529 matching lines @@
     }
 
     private JSONArray toJSONArray(List<String> from) throws JSONException {
         JSONArray result = new JSONArray();
         for (String entry : from) {
             result.put(entry);
         }
         return result;
     }
 }