Allow extension APIs to be called from WebUI.

extensions/common/extension_api.h

Index: extensions/common/extension_api.h
diff --git a/extensions/common/extension_api.h b/extensions/common/extension_api.h
index 77dab818ee0be3b0a88799581c4c57a85d5310cf..8ce02454877500b2cf6196e2bbbaed277d7fef38 100644
--- a/extensions/common/extension_api.h
+++ b/extensions/common/extension_api.h
@@ -109,6 +109,9 @@ class ExtensionAPI {
   bool IsAvailableInUntrustedContext(const std::string& name,
                                      const Extension* extension);
 
+  // Returns true if |name| is available to webui contexts.
+  bool IsAvailableToWebUI(const std::string& name);
+
   // Gets the schema for the extension API with namespace |full_name|.
   // Ownership remains with this object.
   const base::DictionaryValue* GetSchema(const std::string& full_name);