Fix headless_browsertests failures with PlzNavigate.

headless/lib/embedder_mojo_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 "base/optional.h"
 #include "base/path_service.h"
+#include "base/run_loop.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/stringprintf.h"
 #include "base/threading/thread_restrictions.h"
 #include "content/public/test/browser_test.h"
 #include "headless/grit/headless_browsertest_resources.h"
 #include "headless/lib/embedder_test.mojom.h"
 #include "headless/public/devtools/domains/network.h"
 #include "headless/public/devtools/domains/page.h"
 #include "headless/public/devtools/domains/runtime.h"
 #include "headless/public/headless_browser.h"
@@ skipping 200 matching lines @@
 
 class HttpDisabledByDefaultWhenMojoBindingsUsed : public EmbedderMojoTest,
                                                   network::Observer,
                                                   page::Observer {
  public:
   HttpDisabledByDefaultWhenMojoBindingsUsed() {
     EXPECT_TRUE(embedded_test_server()->Start());
   }
 
   void RunMojoTest() override {
+    base::RunLoop run_loop;
     devtools_client_->GetNetwork()->AddObserver(this);
-    devtools_client_->GetNetwork()->Enable();
-  }
-
-  GURL GetInitialUrl() const override {
-    return embedded_test_server()->GetURL("/page_one.html");
+    devtools_client_->GetNetwork()->Enable(run_loop.QuitClosure());
+    base::MessageLoop::ScopedNestableTaskAllower nest_loop(
+        base::MessageLoop::current());
+    run_loop.Run();
+    devtools_client_->GetPage()->AddObserver(this);
+    devtools_client_->GetPage()->Enable();
+    devtools_client_->GetPage()->Navigate(
+        embedded_test_server()->GetURL("/page_one.html").spec());
   }
 
   void ReturnTestResult(const std::string& result) override {
     DisableClientAndFinishAsynchronousTest();
     FAIL() << "The HTTP page should not have been served and we should not have"
               " recieved a mojo callback!";
   }
 
   void OnLoadingFailed(const network::LoadingFailedParams& params) override {
     // The navigation should fail since HTTP requests are blackholed.
     EXPECT_EQ(params.GetErrorText(), "net::ERR_FILE_NOT_FOUND");
     DisableClientAndFinishAsynchronousTest();
   }
 
   void DisableClientAndFinishAsynchronousTest() {
     devtools_client_->GetNetwork()->Disable();
     devtools_client_->GetNetwork()->RemoveObserver(this);
     FinishAsynchronousTest();
   }
 };
 
 DEVTOOLS_CLIENT_TEST_F(HttpDisabledByDefaultWhenMojoBindingsUsed);
 
 }  // namespace headless