headless: Implement client API generation

headless/test/headless_browser_test.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 "headless/test/headless_browser_test.h"
 
 #include "base/files/file_path.h"
 #include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
@@ skipping 80 matching lines @@
 
 bool HeadlessBrowserTest::WaitForLoad(HeadlessWebContents* web_contents) {
   WaitForNavigationObserver observer(this, web_contents);
   RunAsynchronousTest();
   return observer.navigation_succeeded();
 }
 
 void HeadlessBrowserTest::RunAsynchronousTest() {
   base::MessageLoop::ScopedNestableTaskAllower nestable_allower(
       base::MessageLoop::current());
+  EXPECT_FALSE(run_loop_);
   run_loop_ = base::WrapUnique(new base::RunLoop());
   run_loop_->Run();
   run_loop_ = nullptr;
 }
 
 void HeadlessBrowserTest::FinishAsynchronousTest() {
   run_loop_->Quit();
 }
 
 }  // namespace headless