Convert tabs, windows, and extension APIs to feature system.

chrome/common/extensions/api/extension_api_feature.h

Index: chrome/common/extensions/api/extension_api_feature.h
diff --git a/chrome/common/extensions/api/extension_api_feature.h b/chrome/common/extensions/api/extension_api_feature.h
new file mode 100644
index 0000000000000000000000000000000000000000..e0343cfa3385c5d09133eb352722e119c745d61e
--- /dev/null
+++ b/chrome/common/extensions/api/extension_api_feature.h
@@ -0,0 +1,40 @@
+// 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_API_EXTENSION_API_FEATURE_H_
+#define CHROME_COMMON_EXTENSIONS_API_EXTENSION_API_FEATURE_H_
+#pragma once
+
+#include "chrome/common/extensions/feature.h"
+
+#include <map>
+#include <set>
+#include "base/memory/linked_ptr.h"
+
+namespace extensions {
+
+class ExtensionAPIFeature : public Feature {
+ public:
+  ExtensionAPIFeature();
+  virtual ~ExtensionAPIFeature();
+
+  std::set<std::string>* dependencies();
+
+  virtual void Parse(const DictionaryValue* value) OVERRIDE;
+
+  // TODO(aa): Have this return linked_ptr so that we can generate features
+  // on demand for child feature that lack their own spec.
+  Feature* GetChild(const std::string& name) const;
+
+ private:
+  std::set<std::string> dependencies_;
+
+  typedef std::map<std::string,
+                   linked_ptr<ExtensionAPIFeature> > ChildFeatureMap;
+  ChildFeatureMap child_features_;
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_COMMON_EXTENSIONS_API_EXTENSION_API_FEATURE_H_