Remove redundant field initialization in Java code.

components/gcm_driver/instance_id/android/java/src/org/chromium/components/gcm_driver/instance_id/InstanceIDBridge.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.components.gcm_driver.instance_id;
 
 import android.content.Context;
 import android.os.AsyncTask;
 import android.os.Bundle;
 
@@ skipping 11 matching lines @@
  */
 @JNINamespace("instance_id")
 public class InstanceIDBridge {
     private final Context mContext;
     private final String mSubtype;
     private long mNativeInstanceIDAndroid;
     /**
      * Underlying InstanceID. May be shared by multiple InstanceIDBridges. Must be initialized on
      * a background thread.
      */
-    private InstanceID mInstanceID = null;
+    private InstanceID mInstanceID;
 
-    private static boolean sBlockOnAsyncTasksForTesting = false;
+    private static boolean sBlockOnAsyncTasksForTesting;
 
     private InstanceIDBridge(
             long nativeInstanceIDAndroid, Context context, String subtype) {
         mContext = context.getApplicationContext(); // Storing activity context would leak activity.
         mSubtype = subtype;
         mNativeInstanceIDAndroid = nativeInstanceIDAndroid;
     }
 
     /**
      * Returns a wrapped {@link InstanceIDWithSubtype}. Multiple InstanceIDBridge instances may
@@ skipping 172 matching lines @@
                     // Synchronously block the UI thread until doInBackground returns result.
                     result = task.get();
                 } catch (InterruptedException | ExecutionException e) {
                     throw new IllegalStateException(e); // Shouldn't happen in tests.
                 }
                 sendResultToNative(result);
             }
         }
     }
 }