Create a mechanism define declarative rules via the extension manifest.

extensions/common/api/declarative/declarative_manifest_data.h

+// Copyright 2015 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_COMMON_API_DECLARATIVE_DECLARATIVE_MANIFEST_DATA_H_
+#define EXTENSIONS_COMMON_API_DECLARATIVE_DECLARATIVE_MANIFEST_DATA_H_
+
+#include <vector>
+
+#include "base/memory/linked_ptr.h"
+#include "base/strings/string16.h"
+#include "extensions/common/api/events.h"
+#include "extensions/common/extension.h"
+#include "extensions/common/manifest_handler.h"
+
+namespace extensions {
+
+// The parsed form of the "event_rules" manifest entry.
+class DeclarativeManifestData : public Extension::ManifestData {
+ public:
+  typedef extensions::core_api::events::Rule Rule;
+
+  explicit DeclarativeManifestData();

[not at google - send to devlin, 2015/06/08 21:44:58]

explicit not needed on a zero-argument constructor. in fact an explicit
constructor isn't really needed (though actually - perhaps it is - you should
put DISALLOW_COPY_AND_ASSIGN on this class).

[danduong, 2015/06/09 01:21:27]

Done.

+  ~DeclarativeManifestData() override;
+
+  // Gets the DeclarativeManifestData for |extension|, or NULL if none was
+  // specified.
+  static DeclarativeManifestData* Get(const Extension* extension);
+
+  // Tries to construct the info based on |value|, as it would have appeared in
+  // the manifest. Sets |error| and returns an empty scoped_ptr on failure.
+  static scoped_ptr<DeclarativeManifestData> FromValue(const base::Value& value,
+                                                       base::string16* error);
+
+  std::vector<linked_ptr<DeclarativeManifestData::Rule>>& RulesForEvent(
+      const std::string& event);
+
+ private:
+  std::map<std::string, std::vector<linked_ptr<Rule>>> event_rules_map_;
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_COMMON_API_DECLARATIVE_DECLARATIVE_MANIFEST_DATA_H_