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

content/browser/frame_host/render_frame_host_manager_browsertest.cc

 // Copyright 2013 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 <stddef.h>
 #include <stdint.h>
 
 #include <memory>
 #include <set>
 
@@ skipping 129 matching lines @@
       const std::string& original_file_path,
       const net::HostPortPair& host_port_pair,
       std::string* replacement_path) {
     base::StringPairs replacement_text;
     replacement_text.push_back(
         make_pair("REPLACE_WITH_HOST_AND_PORT", host_port_pair.ToString()));
     net::test_server::GetFilePathWithReplacements(
         original_file_path, replacement_text, replacement_path);
   }
 
-  void StartServer() {
+  void SetUpOnMainThread() override {
     // Support multiple sites on the test server.
     host_resolver()->AddRule("*", "127.0.0.1");
+  }
+
+  void StartServer() {
     ASSERT_TRUE(embedded_test_server()->Start());
 
     foo_host_port_ = embedded_test_server()->host_port_pair();
     foo_host_port_.set_host(foo_com_);
   }
 
   void StartEmbeddedServer() {
-    // Support multiple sites on the embedded test server.
     host_resolver()->AddRule("*", "127.0.0.1");
     SetupCrossSiteRedirector(embedded_test_server());
     ASSERT_TRUE(embedded_test_server()->Start());
   }
 
   // Returns a URL on foo.com with the given path.
   GURL GetCrossSiteURL(const std::string& path) {
     GURL cross_site_url(embedded_test_server()->GetURL(path));
     return cross_site_url.ReplaceComponents(replace_host_);
   }
@@ skipping 3214 matching lines @@
     EXPECT_TRUE(ExecuteScript(grandchild, script));
     observer.Wait();
   }
 
   EXPECT_EQ(url, grandchild->current_url());
   ASSERT_EQ(1U, grandchild->child_count());
   EXPECT_EQ(child_url, grandchild->child_at(0)->current_url());
 }
 
 }  // namespace content