PreloadCheck class for extension pre-install checks

extensions/browser/preload_check_test_util.h

+// Copyright 2017 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 EXTENSIONS_BROWSER_PRELOAD_CHECK_TEST_UTIL_H_
+#define EXTENSIONS_BROWSER_PRELOAD_CHECK_TEST_UTIL_H_
+
+#include "extensions/browser/preload_check.h"
+
+namespace extensions {
+
+// Provides a callback method for a PreloadCheck that stores its results.
+class PreloadCheckObserver {
+ public:
+  PreloadCheckObserver();
+  virtual ~PreloadCheckObserver();
+
+  virtual void OnCheckComplete(PreloadCheck::Errors errors);

[Devlin, 2017/03/14 01:44:34]

Given the common utility of this class, it seems like we might be able to have
this be more streamlined.  An easy case would be a GetCallback() method that
returns base::Bind(&OnCheckComplete, base::Unretained(this)) so that you could
just run with Start(observer.GetCheck()).  A more elaborate version would be
allowing to inline the start and wait functionality in a RunUntilComplete() type
method, e.g.
void RunUntilComplete(PreloadCheck* check) {
  check->Start(base::Bind(...));
  base::RunLoop().Run();
}

and then you could just have
Observer observer;
observer.RunUntilComplete(check);

(Having a combination of these can also make sense, since you might not want to
always wait in a blocking fashion.)

[michaelpg, 2017/03/14 21:58:30]

Good idea. Renamed to Runner and added some methods.

+
+  void Wait();
+
+  const PreloadCheck::Errors& errors() const { return errors_; }
+  bool called() const { return called_; }
+
+ private:
+  PreloadCheck::Errors errors_;
+  bool called_;
+
+  DISALLOW_COPY_AND_ASSIGN(PreloadCheckObserver);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_PRELOAD_CHECK_TEST_UTIL_H_