Remove redundant field initialization in Java code.

chrome/android/java/src/org/chromium/chrome/browser/crash/MinidumpUploadRetry.java

 // Copyright 2015 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.crash;
 
 import android.content.Context;
 import android.os.Handler;
 
 import org.chromium.base.NonThreadSafe;
 import org.chromium.base.annotations.SuppressFBWarnings;
 import org.chromium.net.ConnectionType;
 import org.chromium.net.NetworkChangeNotifier;
 
 /**
  * This class listens to network changes and determine when it would good to
  * retry uploading minidumps.
  */
 class MinidumpUploadRetry implements NetworkChangeNotifier.ConnectionTypeObserver {
     private final Context mContext;
-    private static MinidumpUploadRetry sSingleton = null;
+    private static MinidumpUploadRetry sSingleton;
 
     private static class Scheduler implements Runnable {
         private static NonThreadSafe sThreadCheck;
         private final Context mContext;
 
         private Scheduler(Context context) {
             this.mContext = context;
         }
 
         @Override
@@ skipping 33 matching lines @@
         // know what the user's crash upload preference is until
         // the time when we are actually uploading.
         if (connectionType == ConnectionType.CONNECTION_NONE) {
             return;
         }
         MinidumpUploadService.tryUploadAllCrashDumps(mContext);
         NetworkChangeNotifier.removeConnectionTypeObserver(this);
         sSingleton = null;
     }
 }