Support [TypeChecking] on dependent/partial interfaces.

Source/bindings/scripts/interface_dependency_resolver.py

Index: Source/bindings/scripts/interface_dependency_resolver.py
diff --git a/Source/bindings/scripts/interface_dependency_resolver.py b/Source/bindings/scripts/interface_dependency_resolver.py
index c1f220fb59b1fc9db6e96b4fb7d74ecd9ea901b7..0db1ca18328fd4551dcad32a81f5a54c1055dca0 100644
--- a/Source/bindings/scripts/interface_dependency_resolver.py
+++ b/Source/bindings/scripts/interface_dependency_resolver.py
@@ -44,11 +44,16 @@ from utilities import idl_filename_to_component, is_valid_component_dependency
 # 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 = set([
-    'Conditional',
-    'PerContextEnabled',
-    'RuntimeEnabled',
-])
+#
+# Paired with the extended attribute name is its value type; needed to be able
+# to correctly merge interface-level occurrences with ones that may
+# be present on the method/attribute/constant.
+DEPENDENCY_EXTENDED_ATTRIBUTES = {
+    'Conditional': 'string',
+    'PerContextEnabled': 'string',
+    'RuntimeEnabled': 'string',
+    'TypeChecking': 'list',
+}
 
 
 class InterfaceDependencyResolver(object):
@@ -243,7 +248,7 @@ def transfer_extended_attributes(dependency_interface, dependency_interface_base
     merged_extended_attributes = dict(
         (key, value)
         for key, value in dependency_interface.extended_attributes.iteritems()
-        if key in DEPENDENCY_EXTENDED_ATTRIBUTES)
+        if key in DEPENDENCY_EXTENDED_ATTRIBUTES.keys())
 
     # A partial interface's members are implemented as static member functions
     # in a separate C++ class. This class name is stored in
@@ -274,9 +279,26 @@ def transfer_extended_attributes(dependency_interface, dependency_interface_base
             dependency_interface.extended_attributes.get(
                 'ImplementedAs', dependency_interface_basename))
 
+    def update_attributes(attributes, extras):
+        def to_list(x):
+            if type(x) is list:
+                return x
+            else:
+                return [x]
+
+        for key, value in extras.items():
+            if key in attributes:
+                # Interface-level extended attributes do not take precedence
+                # over same attribute at the method/attribute/const-level.
+                # If the attribute value is a list, the two are combined.
+                if DEPENDENCY_EXTENDED_ATTRIBUTES[key] == 'list':
+                    attributes[key] = to_list(attributes[key]) + to_list(value)
+            else:
+                attributes[key] = value
+
     for attribute in dependency_interface.attributes:
-        attribute.extended_attributes.update(merged_extended_attributes)
+        update_attributes(attribute.extended_attributes, merged_extended_attributes)
     for constant in dependency_interface.constants:
-        constant.extended_attributes.update(merged_extended_attributes)
+        update_attributes(constant.extended_attributes, merged_extended_attributes)
     for operation in dependency_interface.operations:
-        operation.extended_attributes.update(merged_extended_attributes)
+        update_attributes(operation.extended_attributes, merged_extended_attributes)