Ensure all content_browsertests call the host resolver in SetUpOnMainThread and not after.

content/browser/web_contents/opened_by_dom_browsertest.cc

 // 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.
 
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/strings/stringprintf.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/test/browser_test_utils.h"
@@ skipping 29 matching lines @@
 
 }  // namespace
 
 class OpenedByDOMTest : public ContentBrowserTest {
  protected:
   void SetUpCommandLine(base::CommandLine* command_line) override {
     // Use --site-per-process to force process swaps on cross-site navigations.
     IsolateAllSitesForTesting(command_line);
   }
 
+  void SetUpOnMainThread() override {
+    host_resolver()->AddRule("*", "127.0.0.1");
+  }
+
   bool AttemptCloseFromJavaScript(WebContents* web_contents) {
     CloseTrackingDelegate close_tracking_delegate;
     WebContentsDelegate* old_delegate = web_contents->GetDelegate();
     web_contents->SetDelegate(&close_tracking_delegate);
 
     const char kCloseWindowScript[] =
         // Close the window.
         "window.close();"
         // Report back after an event loop iteration; the close IPC isn't sent
         // immediately.
@@ skipping 47 matching lines @@
   NavigateToURL(shell(), url1);
 
   Shell* popup = OpenWindowFromJavaScript(shell(), url2);
   NavigateToURL(popup, url3);
   EXPECT_TRUE(AttemptCloseFromJavaScript(popup->web_contents()));
 }
 
 // Tests that window.close() works in a popup window that has navigated a few
 // times and swapped processes.
 IN_PROC_BROWSER_TEST_F(OpenedByDOMTest, CrossProcessPopup) {
-  host_resolver()->AddRule("*", "127.0.0.1");
   ASSERT_TRUE(embedded_test_server()->Start());
 
   GURL url1 = embedded_test_server()->GetURL("/site_isolation/blank.html?1");
 
   GURL url2 = embedded_test_server()->GetURL("/site_isolation/blank.html?2");
   GURL::Replacements replace_host;
   replace_host.SetHostStr("foo.com");
   url2 = url2.ReplaceComponents(replace_host);
 
   GURL url3 = embedded_test_server()->GetURL("/site_isolation/blank.html?3");
   url3 = url3.ReplaceComponents(replace_host);
 
   NavigateToURL(shell(), url1);
 
   Shell* popup = OpenWindowFromJavaScript(shell(), url2);
   NavigateToURL(popup, url3);
   EXPECT_TRUE(AttemptCloseFromJavaScript(popup->web_contents()));
 }
 
 }  // namespace content