Implement '[SecureContext]' IDL attribute for partial interfaces.

third_party/WebKit/Source/bindings/scripts/interface_dependency_resolver.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 29 matching lines @@
 from utilities import idl_filename_to_component, is_valid_component_dependency, merge_dict_recursively
 
 # The following extended attributes can be applied to a dependency interface,
 # and are then applied to the individual members when merging.
 # Note that this moves the extended attribute from the interface to the member,
 # which changes the semantics and yields different code than the same extended
 # attribute on the main interface.
 DEPENDENCY_EXTENDED_ATTRIBUTES = frozenset([
     'OriginTrialEnabled',
     'RuntimeEnabled',
+    'SecureContext',
 ])
 
 
 class InterfaceDependencyResolver(object):
     def __init__(self, interfaces_info, reader):
         """Initialize dependency resolver.
 
         Args:
             interfaces_info:
                 dict of interfaces information, from compute_dependencies.py
@@ skipping 196 matching lines @@
     The data storing consists of:
     * moving certain extended attributes from the dependency interface
       to its members (deleting the extended attribute from the interface)
     * storing the C++ class of the implementation in an internal
       extended attribute of each member, [PartialInterfaceImplementedAs]
 
     No return: modifies dependency_interface in place.
     """
     merged_extended_attributes = {}
     for key in DEPENDENCY_EXTENDED_ATTRIBUTES:
-        value = dependency_interface.extended_attributes.get(key)
-        if not value:
+        if key not in dependency_interface.extended_attributes:
             continue
 
-        merged_extended_attributes[key] = value
+        merged_extended_attributes[key] = dependency_interface.extended_attributes[key]
         # Remove the merged attributes from the original dependency interface.
         # This ensures that if other dependency interfaces are merged onto this
         # one, its extended_attributes do not leak through
         # (https://crbug.com/603782).
         del dependency_interface.extended_attributes[key]
 
     # A partial interface's members are implemented as static member functions
     # in a separate C++ class. This class name is stored in
     # [PartialInterfaceImplementedAs] which defaults to the basename of
     # dependency IDL file.
@@ skipping 65 matching lines @@
             # This loop may process the same interface many times, so it's
             # possible that we're adding the same attributes twice or more.
             # So check if there is a duplicate.
             for attr in inherited_unforgeable_attributes:
                 if attr not in interface.attributes:
                     interface.attributes.append(attr)
             referenced_interfaces.extend(interface_info.get('referenced_interfaces', []))
             interface_info['referenced_interfaces'] = sorted(set(referenced_interfaces))
             merge_dict_recursively(interface_info,
                                    {'cpp_includes': {component: cpp_includes}})