Remove redundant field initialization in Java code.

printing/android/java/src/org/chromium/printing/PrintDocumentAdapterWrapper.java

Index: printing/android/java/src/org/chromium/printing/PrintDocumentAdapterWrapper.java
diff --git a/printing/android/java/src/org/chromium/printing/PrintDocumentAdapterWrapper.java b/printing/android/java/src/org/chromium/printing/PrintDocumentAdapterWrapper.java
index 676b8d01a2579a4c1a3f6d42980562a75aef17ad..b1b74cfcda0b608227b18d018bd31798a9d12616 100644
--- a/printing/android/java/src/org/chromium/printing/PrintDocumentAdapterWrapper.java
+++ b/printing/android/java/src/org/chromium/printing/PrintDocumentAdapterWrapper.java
@@ -56,7 +56,7 @@ public class PrintDocumentAdapterWrapper extends PrintDocumentAdapter {
     }
 
     public static class LayoutResultCallbackWrapperImpl implements LayoutResultCallbackWrapper {
-        private LayoutResultCallback mCallback = null;
+        private LayoutResultCallback mCallback;
         public LayoutResultCallbackWrapperImpl(LayoutResultCallback callback) {
             assert callback != null;
             mCallback = callback;
@@ -79,7 +79,7 @@ public class PrintDocumentAdapterWrapper extends PrintDocumentAdapter {
     }
 
     public static class WriteResultCallbackWrapperImpl implements WriteResultCallbackWrapper {
-        private WriteResultCallback mCallback = null;
+        private WriteResultCallback mCallback;
         public WriteResultCallbackWrapperImpl(WriteResultCallback callback) {
             assert callback != null;
             mCallback = callback;