[Extensions Bindings] Add support for custom property types

extensions/renderer/storage_area.h

Index: extensions/renderer/storage_area.h
diff --git a/extensions/renderer/storage_area.h b/extensions/renderer/storage_area.h
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+++ b/extensions/renderer/storage_area.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_RENDERER_STORAGE_AREA_H_
+#define EXTENSIONS_RENDERER_STORAGE_AREA_H_
+
+#include <map>
+#include <string>
+
+#include "base/macros.h"
+#include "base/strings/string_piece.h"
+#include "v8/include/v8.h"
+
+namespace gin {
+class Arguments;
+}
+
+namespace extensions {
+class APIRequestHandler;
+class APISignature;
+class APITypeReferenceMap;
+
+// Implementation of the storage.StorageArea custom type used in the
+// chrome.storage API.
+class StorageArea {
+ public:
+  StorageArea(APIRequestHandler* request_handler,
+              const APITypeReferenceMap* type_refs,
+              const std::string& name);
+  ~StorageArea();
+
+  // Creates a StorageArea object for the given context and property name.
+  static v8::Local<v8::Object> CreateStorageArea(
+      v8::Local<v8::Context> context,
+      const std::string& property_name,
+      APIRequestHandler* request_handler,
+      APITypeReferenceMap* type_refs);
+
+  void HandleFunctionCall(const std::string& method_name,
+                          gin::Arguments* arguments);
+
+ private:
+  // Returns the schema associated with the specified function.
+  // TODO(devlin): Other custom types will need this, too; move it out of here
+  // when more exist.
+  const APISignature& GetFunctionSchema(base::StringPiece api_name,
+                                        base::StringPiece type_name,
+                                        base::StringPiece function_name);
+
+  APIRequestHandler* request_handler_;
+
+  const APITypeReferenceMap* type_refs_;
+
+  std::string name_;
+
+  // TODO(devlin): See GetFunctionSchema.
+  std::map<std::string, std::unique_ptr<APISignature>> signatures_;
+
+  DISALLOW_COPY_AND_ASSIGN(StorageArea);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_RENDERER_STORAGE_AREA_H_