Reland r130462: Implement FeatureProvider for ExtensionAPI."

chrome/common/extensions/simple_feature_provider.h

 // Copyright (c) 2012 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_COMMON_EXTENSIONS_SIMPLE_FEATURE_PROVIDER_H_
 #define CHROME_COMMON_EXTENSIONS_SIMPLE_FEATURE_PROVIDER_H_
 #pragma once
 
 #include <set>
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/values.h"
 #include "chrome/common/extensions/feature.h"
+#include "chrome/common/extensions/feature_provider.h"
 
 namespace extensions {
 
 // Reads Features out of a simple JSON file description.
-class SimpleFeatureProvider {
+class SimpleFeatureProvider : public FeatureProvider {
  public:
-  // Create an instance for an arbitrary hunk of JSON. This is typically used
-  // during tests.
-  explicit SimpleFeatureProvider(scoped_ptr<DictionaryValue> root);
-  ~SimpleFeatureProvider();
+  typedef Feature*(*FeatureFactory)();
+
+  // Creates a new SimpleFeatureProvider. Pass null to |factory| to have the
+  // provider create plain old Feature instances.
+  SimpleFeatureProvider(scoped_ptr<DictionaryValue> root,
+                        FeatureFactory factory);
+  virtual ~SimpleFeatureProvider();
 
   // Gets an instance for the _manifest_features.json file that is baked into
   // Chrome as a resource.
   static SimpleFeatureProvider* GetManifestFeatures();
 
   // Gets an instance for the _permission_features.json file that is baked into
   // Chrome as a resource.
   static SimpleFeatureProvider* GetPermissionFeatures();
 
   // Returns all features described by this instance.
   std::set<std::string> GetAllFeatureNames() const;
 
   // Gets the feature |feature_name|, if it exists.
-  scoped_ptr<Feature> GetFeature(const std::string& feature_name) const;
+  virtual scoped_ptr<Feature> GetFeature(
+      const std::string& feature_name) OVERRIDE;
 
  private:
   scoped_ptr<DictionaryValue> root_;
+  FeatureFactory factory_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_COMMON_EXTENSIONS_SIMPLE_FEATURE_PROVIDER_H_