headless: Add support for host resolver mapping

headless/lib/headless_browser_browsertest.cc

 // Copyright 2016 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.
 
 #include <memory>
 
 #include "content/public/test/browser_test.h"
 #include "headless/public/headless_browser.h"
 #include "headless/public/headless_web_contents.h"
 #include "headless/test/headless_browser_test.h"
@@ skipping 60 matching lines @@
   // from headless/test/data as expected. We should fix this.
   HeadlessWebContents* web_contents = browser()->CreateWebContents(
       GURL("http://not-an-actual-domain.tld/hello.html"), gfx::Size(800, 600));
   EXPECT_TRUE(WaitForLoad(web_contents));
   EXPECT_EQ(static_cast<size_t>(1), browser()->GetAllWebContents().size());
   EXPECT_EQ(web_contents, browser()->GetAllWebContents()[0]);
   web_contents->Close();
   EXPECT_TRUE(browser()->GetAllWebContents().empty());
 }
 
+IN_PROC_BROWSER_TEST_F(HeadlessBrowserTest, SetHostResolverRules) {
+  EXPECT_TRUE(embedded_test_server()->Start());
+  HeadlessBrowser::Options::Builder builder;
+  builder.SetHostResolverRules("MAP not-an-actual-domain.tld 127.0.0.1");
+  SetBrowserOptions(builder.Build());
+
+  // Load a page which doesn't actually exist, but which is turned into a valid
+  // address by our host resolver rules.
+  HeadlessWebContents* web_contents = browser()->CreateWebContents(
+      GURL("http://not-an-actual-domain.tld/hello.html"), gfx::Size(800, 600));
+  EXPECT_TRUE(WaitForLoad(web_contents));
+}
+
 }  // namespace headless