Taking screenshots while running a test

chrome/browser/chromeos/login/screenshot_tester.h

+// 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.
+
+#ifndef CHROME_BROWSER_CHROMEOS_LOGIN_SCREENSHOT_TESTER_H_
+#define CHROME_BROWSER_CHROMEOS_LOGIN_SCREENSHOT_TESTER_H_
+
+#include "base/base_export.h"
+#include "base/bind_internal.h"
+#include "base/files/file_path.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted_memory.h"
+#include "base/memory/weak_ptr.h"
+#include "base/run_loop.h"
+
+namespace chromeos {
+
+// A class that allows taking, saving and comparing screnshots while
+// running tests.
+class ScreenshotTester {
+ public:
+  ScreenshotTester();
+  virtual ~ScreenshotTester();
+
+  // Returns true if the screenshots should be taken and will be taken,
+  // false otherwise. Also gets all the information from the command line
+  // swithes.
+  bool TryInitialize();
+
+  // Does all the work that has been stated through switches:
+  // updates golden screenshot or takes a new screenshot and compares it
+  // with the golden one (this part is not implemented yet).
+  void Run(const std::string& file_name);
+
+ private:
+  typedef scoped_refptr<base::RefCountedBytes> PNGFile;
+
+  // Takes a screenshot and puts it to |screenshot_| field.
+  void TakeScreenshot();
+
+  // Saves |png_data| as a new golden screenshot for this test.
+  void UpdateGoldenScreenshot(const std::string& file_name, PNGFile png_data);
+
+  // Saves |png_data| as a current screenshot.
+  void ReturnScreenshot(PNGFile png_data);
+
+  // Path to the directory for golden screenshots.
+  base::FilePath screenshot_dest_;
+
+  // |run_loop_| and |run_loop_quitter_| are used to synchronize
+  // with ui::GrabWindowSnapshotAsync.
+  base::RunLoop run_loop_;
+  base::Closure run_loop_quitter_;
+
+  // Current screenshot.
+  PNGFile screenshot_;
+
+  // Is true when we running updating golden screenshots mode.
+  bool update_golden_screenshot_;
+  base::WeakPtrFactory<ScreenshotTester> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScreenshotTester);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SCREENSHOT_TESTER_H_