SupportsUserData and manifest handlers for Extension; use them for the Omnibox API.

chrome/common/extensions/manifest_handler.h

Index: chrome/common/extensions/manifest_handler.h
diff --git a/chrome/common/extensions/manifest_handler.h b/chrome/common/extensions/manifest_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..89e65093880121cca7f4e5cc15f078d2e7db9669
--- /dev/null
+++ b/chrome/common/extensions/manifest_handler.h
@@ -0,0 +1,52 @@
+// 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_MANIFEST_HANDLER_H_
+#define CHROME_COMMON_EXTENSIONS_MANIFEST_HANDLER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/string16.h"
+
+namespace base {
+class Value;
+}
+
+namespace extensions {
+
+class Extension;
+
+class ManifestHandler {
+ public:
+  ManifestHandler();
+  virtual ~ManifestHandler();
+
+  // Attempts to parse the manifest value.
+  // Returns true on success or false on failure; if false, |error| will
+  // be set to a failure message.
+  virtual bool Parse(const base::Value* value,
+                     Extension* extension,
+                     string16* error) = 0;
+
+  // Associate |handler| with |key| in the manifest. Takes ownership
+  // of |handler|. TODO(yoz): Decide how to handle dotted subkeys.
+  // WARNING: Manifest handlers registered only in the browser process
+  // are not available to renderers.
+  static void Register(const std::string& key, ManifestHandler* handler);
+
+  // Get the manifest handler associated with |key|, or NULL
+  // if there is none.
+  static ManifestHandler* Get(const std::string& key);
+
+  // If the handler is not handling most of the keys, it may be
+  // more efficient to have a list of keys to iterate over.
+  // TODO(yoz): this isn't the long-term solution.
+  static std::vector<std::string> GetKeys();
+};
+
+
+}  // namespace extensions
+
+#endif  // CHROME_COMMON_EXTENSIONS_MANIFEST_HANDLER_H_