Add method getAllHeaders to HttpUrlRequest.

components/cronet/android/java/src/org/chromium/net/HttpUrlConnectionUrlRequest.java

 // Copyright 2014 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.net;
 
 import android.content.Context;
 import android.text.TextUtils;
 
 import org.apache.http.HttpStatus;
@@ skipping 458 matching lines @@
     @Override
     public long getContentLength() {
         return mContentLength;
     }
 
     @Override
     public String getContentType() {
         return mContentType;
     }
 
-
     @Override
     public String getHeader(String name) {
         if (mConnection == null) {
             throw new IllegalStateException("Response headers not available");
         }
         Map<String, List<String>> headerFields = mConnection.getHeaderFields();
         if (headerFields != null) {
             List<String> headerValues = headerFields.get(name);
             if (headerValues != null) {
                 return TextUtils.join(", ", headerValues);
             }
         }
         return null;
     }
 
+    @Override
+    public Map<String, List<String>> getAllHeaders() {
+        if (mConnection == null) {
+            throw new IllegalStateException("Response headers not available");
+        }
+        return mConnection.getHeaderFields();
+    }
+
     private void validateNotStarted() {
         if (mStarted) {
             throw new IllegalStateException("Request already started");
         }
     }
 }