[android_webview] Support null AwWebResourceResponse headers.

android_webview/java/src/org/chromium/android_webview/AwWebResourceResponse.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.android_webview;
 
 import org.chromium.base.CalledByNative;
 import org.chromium.base.JNINamespace;
 
 import java.io.InputStream;
@@ skipping 18 matching lines @@
         mData = data;
     }
 
     public AwWebResourceResponse(String mimeType, String encoding, InputStream data,
             int statusCode, String reasonPhrase, Map<String, String> responseHeaders) {
         this(mimeType, encoding, data);
 
         mStatusCode = statusCode;
         mReasonPhrase = reasonPhrase;
 
-        mResponseHeaderNames = new String[responseHeaders.size()];
-        mResponseHeaderValues = new String[responseHeaders.size()];
-        int i = 0;
-        for (Map.Entry<String, String> entry : responseHeaders.entrySet()) {
-            mResponseHeaderNames[i] = entry.getKey();
-            mResponseHeaderValues[i] = entry.getValue();
-            i++;
+        if (responseHeaders != null) {
+            mResponseHeaderNames = new String[responseHeaders.size()];
+            mResponseHeaderValues = new String[responseHeaders.size()];
+            int i = 0;
+            for (Map.Entry<String, String> entry : responseHeaders.entrySet()) {
+                mResponseHeaderNames[i] = entry.getKey();
+                mResponseHeaderValues[i] = entry.getValue();
+                i++;
+            }
         }
     }
 
     @CalledByNative
     public String getMimeType() {
         return mMimeType;
     }
 
     @CalledByNative
     public String getCharset() {
@@ skipping 18 matching lines @@
     @CalledByNative
     public String[] getResponseHeaderNames() {
         return mResponseHeaderNames;
     }
 
     @CalledByNative
     public String[] getResponseHeaderValues() {
         return mResponseHeaderValues;
     }
 }