Remove redundant field initialization in Java code.

ui/android/java/src/org/chromium/ui/base/SelectFileDialog.java

 // Copyright 2012 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.ui.base;
 
 import android.Manifest;
 import android.annotation.TargetApi;
 import android.app.Activity;
 import android.content.ClipData;
@@ skipping 36 matching lines @@
     private static final String VIDEO_TYPE = "video/";
     private static final String AUDIO_TYPE = "audio/";
     private static final String ALL_IMAGE_TYPES = IMAGE_TYPE + "*";
     private static final String ALL_VIDEO_TYPES = VIDEO_TYPE + "*";
     private static final String ALL_AUDIO_TYPES = AUDIO_TYPE + "*";
     private static final String ANY_TYPES = "*/*";
 
     /**
      * If set, overrides the WindowAndroid passed in {@link selectFile()}.
      */
-    private static WindowAndroid sOverrideWindowAndroid = null;
+    private static WindowAndroid sOverrideWindowAndroid;
 
     private final long mNativeSelectFileDialog;
     private List<String> mFileTypes;
     private boolean mCapture;
     private boolean mAllowMultiple;
     private Uri mCameraOutputUri;
     private WindowAndroid mWindowAndroid;
 
     private boolean mSupportsImageCapture;
     private boolean mSupportsVideoCapture;
@@ skipping 383 matching lines @@
     private static SelectFileDialog create(long nativeSelectFileDialog) {
         return new SelectFileDialog(nativeSelectFileDialog);
     }
 
     private native void nativeOnFileSelected(long nativeSelectFileDialogImpl,
             String filePath, String displayName);
     private native void nativeOnMultipleFilesSelected(long nativeSelectFileDialogImpl,
             String[] filePathArray, String[] displayNameArray);
     private native void nativeOnFileNotSelected(long nativeSelectFileDialogImpl);
 }