headless: Implement screenshot capturing

headless/lib/headless_devtools_client_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/domains/network.h"
 #include "headless/public/domains/page.h"
 #include "headless/public/domains/runtime.h"
 #include "headless/public/headless_browser.h"
 #include "headless/public/headless_devtools_client.h"
 #include "headless/public/headless_devtools_target.h"
 #include "headless/public/headless_web_contents.h"
 #include "headless/test/headless_browser_test.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/geometry/size.h"
 #include "url/gurl.h"
 
 namespace headless {
 
 #define DEVTOOLS_CLIENT_TEST_F(TEST_FIXTURE_NAME)                        \
   IN_PROC_BROWSER_TEST_F(TEST_FIXTURE_NAME, RunAsyncTest) { RunTest(); } \
   class AsyncHeadlessBrowserTestNeedsSemicolon##TEST_FIXTURE_NAME {}
 
 // A test fixture which attaches a devtools client before starting the test.
+// TODO(eseckler): Use the reusable HeadlessAsyncDevTooledTest and macro from
+// headless_browser_test.h instead of this class.
 class HeadlessDevToolsClientTest : public HeadlessBrowserTest,
                                    public HeadlessWebContents::Observer {
  public:
   HeadlessDevToolsClientTest()
       : devtools_client_(HeadlessDevToolsClient::Create()) {}
   ~HeadlessDevToolsClientTest() override {}
 
   // HeadlessWebContentsObserver implementation:
   void DevToolsTargetReady() override {
     EXPECT_TRUE(web_contents_->GetDevToolsTarget());
@@ skipping 167 matching lines @@
 
   void OnFrameStoppedLoading(
       const page::FrameStoppedLoadingParams& params) override {
     FinishAsynchronousTest();
   }
 };
 
 DEVTOOLS_CLIENT_TEST_F(HeadlessDevToolsClientExperimentalTest);
 
 }  // namespace headless