Replicating LayoutDumpFlags across OOPIFs.

components/test_runner/tracked_dictionary.h

+// 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.
+
+#ifndef COMPONENTS_TEST_RUNNER_TRACKED_DICTIONARY_H_
+#define COMPONENTS_TEST_RUNNER_TRACKED_DICTIONARY_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/values.h"
+#include "components/test_runner/test_runner_export.h"
+
+namespace test_runner {
+
+// TrackedDictionary wraps base::DictionaryValue, but forces all mutations to go
+// through TrackedDictionary's Set methods.  This allows tracking of changes
+// accumulated since the last call to ResetChangeTracking.
+class TEST_RUNNER_EXPORT TrackedDictionary {
+ public:
+  TrackedDictionary();
+
+  // Current value of the tracked dictionary.
+  const base::DictionaryValue& current_values() const {
+    return current_values_;
+  }
+
+  // Subset of |current_values| that have been changed (i.e. via Set method)
+  // since the last call to ResetChangeTracking.
+  const base::DictionaryValue& changed_values() const {
+    return changed_values_;
+  }
+
+  // Clears out |changed_values|.
+  void ResetChangeTracking();
+
+  // Overwrites |current_values| with values present in |new_changes|.
+  // The new values are not present in |changed_values| afterwards.
+  void ApplyUntrackedChanges(const base::DictionaryValue& new_changes);
+
+  // Sets a value in |current_values| and tracks the change in |changed_values|.
+  void Set(const std::string& path, scoped_ptr<base::Value> new_value);
+
+  // Type-specific setter for convenience.
+  void SetBoolean(const std::string& path, bool new_value);
+
+ private:
+  base::DictionaryValue current_values_;
+  base::DictionaryValue changed_values_;
+
+  DISALLOW_COPY_AND_ASSIGN(TrackedDictionary);
+};
+
+}  // namespace test_runner
+
+#endif  // COMPONENTS_TEST_RUNNER_TRACKED_DICTIONARY_H_