[android_webview] Support null AwWebResourceResponse headers.

android_webview/javatests/src/org/chromium/android_webview/test/AwContentsClientShouldInterceptRequestTest.java

Index: android_webview/javatests/src/org/chromium/android_webview/test/AwContentsClientShouldInterceptRequestTest.java
diff --git a/android_webview/javatests/src/org/chromium/android_webview/test/AwContentsClientShouldInterceptRequestTest.java b/android_webview/javatests/src/org/chromium/android_webview/test/AwContentsClientShouldInterceptRequestTest.java
index e1bcb59fbff68cbabf4c3b1686847cb21c992c8e..34c0511f30a46c4b725df919dc55f41777cfe5bd 100644
--- a/android_webview/javatests/src/org/chromium/android_webview/test/AwContentsClientShouldInterceptRequestTest.java
+++ b/android_webview/javatests/src/org/chromium/android_webview/test/AwContentsClientShouldInterceptRequestTest.java
@@ -465,6 +465,9 @@ public class AwContentsClientShouldInterceptRequestTest extends AwTestBase {
             "  return xhr.getResponseHeader('" + headerName + "');" +
             "})();";
         String header = executeJavaScriptAndWaitForResult(awContents, contentsClient, syncGetJs);
+
+        if (header.equals("null"))
+            return null;
         // JSON stringification applied by executeJavaScriptAndWaitForResult adds quotes
         // around returned strings.
         assertTrue(header.length() > 2);
@@ -516,6 +519,20 @@ public class AwContentsClientShouldInterceptRequestTest extends AwTestBase {
                 getHeaderValue(mAwContents, mContentsClient, syncGetUrl, clientResponseHeaderName));
     }
 
+    @SmallTest
+    @Feature({"AndroidWebView"})
+    public void testNullHttpResponseHeaders() throws Throwable {
+        final String syncGetUrl = mWebServer.getResponseUrl("/intercept_me");
+        enableJavaScriptOnUiThread(mAwContents);
+
+        final String aboutPageUrl = addAboutPageToTestServer(mWebServer);
+        loadUrlSync(mAwContents, mContentsClient.getOnPageFinishedHelper(), aboutPageUrl);
+
+        mShouldInterceptRequestHelper.setReturnValue(
+                new AwWebResourceResponse("text/html", "UTF-8", null, 0, null, null));
+        assertEquals(null, getHeaderValue(mAwContents, mContentsClient, syncGetUrl, "Some-Header"));
+    }
+
     private String makePageWithTitle(String title) {
         return CommonResources.makeHtmlPageFrom("<title>" + title + "</title>",
                 "<div> The title is: " + title + " </div>");