PreloadCheckGroup for managing multiple extension PreloadChecks

extensions/browser/preload_check_group.h

Index: extensions/browser/preload_check_group.h
diff --git a/extensions/browser/preload_check_group.h b/extensions/browser/preload_check_group.h
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+// 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_GROUP_H_
+#define EXTENSIONS_BROWSER_PRELOAD_CHECK_GROUP_H_
+
+#include <memory>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "base/strings/string16.h"
+#include "extensions/browser/preload_check.h"
+#include "extensions/common/extension.h"
+
+namespace extensions {
+
+// Starts a collection of PreloadChecks and reports any errors once all
+// checks have completed or, if configured to "fail fast", when the first error
+// or set of errors occurs.
+class PreloadCheckGroup : public PreloadCheck {
+ public:
+  PreloadCheckGroup(scoped_refptr<Extension> extension,
+                    const std::vector<PreloadCheck*>& checks,
+                    bool fail_fast);
+  ~PreloadCheckGroup() override;
+
+  void AddCheck(PreloadCheck* check);
+
+  // PreloadCheck:
+  void Start(ResultCallback callback) override;
+  // base::string16 GetErrorMessage() const override;
+
+ private:
+  // Saves any errors and may invoke the callback.
+  void OnCheckComplete(PreloadCheck* check, Errors errors);
+
+  // Invokes the callback if the checks are considered finished.
+  void MaybeInvokeCallback();
+
+  // If true, the callback is invoked when the first check fails.
+  bool fail_fast_;
+
+  // Number of currently running checks.
+  int running_checks_;
+
+  // Errors found so far.
+  Errors errors_;
+  /*
+  // Only the first non-empty error string is recorded.
+  mutable base::string16 error_;
+  */
+
+  // Checks to run.
+  std::vector<PreloadCheck*> checks_;
+
+  // The callback to invoke when checks are complete.
+  ResultCallback callback_;
+
+  base::WeakPtrFactory<PreloadCheckGroup> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(PreloadCheckGroup);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_PRELOAD_CHECK_GROUP_H_