IDL compiler: Disable to put [Unforgeable] on interfaces or static members

In WebIDL spec, [Unforgeable] can appear on interface attributes
and interface non-static operations.
https://heycam.github.io/webidl/#Unforgeable

Now our IDL compiler does not check its use cases.
This CL makes IDL compiler to check if [Unforgeable] appears on
interfaces or static members, and stops with a warning message
if it does.


Bug: 674593
Change-Id: I6f17834eae71b3c7aa44556c3442f679091efd59
Reviewed-on: https://chromium-review.googlesource.com/1198711Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Hitoshi Yoshida <peria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587973}

third_party/blink/renderer/bindings/IDLExtendedAttributes.md

@@ -508,12 +508,11 @@ Standard: [Unforgeable](http://heycam.github.io/webidl/#Unforgeable)
 
 Summary: Makes interface members unconfigurable and also controls where the member is defined.
 
-Usage: Can be specified on methods, attributes or interfaces:
+Usage: Can be specified on interface methods or non-static interface attributes:
 
 ```webidl
 [Unforgeable] void func();
 [Unforgeable] attribute DOMString str;
-[Unforgeable] interface XXX { ... };
 ```
 
 By default, interface members are configurable (i.e. you can modify a property descriptor corresponding to the member and also you can delete the property). `[Unforgeable]` makes the member unconfiguable so that you cannot modify or delete the property corresponding to the member.

third_party/blink/renderer/bindings/scripts/compute_interfaces_info_individual.py

@@ -137,8 +137,6 @@ def get_put_forward_interfaces_from_definition(definition):
 
 
 def get_unforgeable_attributes_from_definition(definition):
-    if 'Unforgeable' in definition.extended_attributes:
-        return sorted(definition.attributes)
     return sorted(attribute for attribute in definition.attributes
                   if 'Unforgeable' in attribute.extended_attributes)
 

third_party/blink/renderer/bindings/scripts/idl_definitions.py

@@ -383,6 +383,9 @@ class IdlInterface(object):
                 raise ValueError('Value iterators (iterable<V>) must be accompanied by an indexed '
                                  'property getter and an integer-typed length attribute.')
 
+        if 'Unforgeable' in self.extended_attributes:
+            raise ValueError('[Unforgeable] cannot appear on interfaces.')
+
     def accept(self, visitor):
         visitor.visit_interface(self)
         for attribute in self.attributes:
@@ -450,6 +453,9 @@ class IdlAttribute(TypedObject):
                 else:
                     raise ValueError('Unrecognized node class: %s' % child_class)
 
+        if 'Unforgeable' in self.extended_attributes and self.is_static:
+            raise ValueError('[Unforgeable] cannot appear on static attributes.')
+
     def accept(self, visitor):
         visitor.visit_attribute(self)
 
@@ -575,6 +581,9 @@ class IdlOperation(TypedObject):
             else:
                 raise ValueError('Unrecognized node class: %s' % child_class)
 
+        if 'Unforgeable' in self.extended_attributes and self.is_static:
+            raise ValueError('[Unforgeable] cannot appear on static operations.')
+
     @classmethod
     def constructor_from_arguments_node(cls, name, arguments_node):
         constructor = cls()

third_party/blink/renderer/bindings/scripts/v8_attributes.py

@@ -185,7 +185,7 @@ def attribute_context(interface, attribute, interfaces):
         'is_save_same_object': is_save_same_object,
         'is_static': attribute.is_static,
         'is_url': 'URL' in extended_attributes,
-        'is_unforgeable': is_unforgeable(interface, attribute),
+        'is_unforgeable': is_unforgeable(attribute),
         'on_instance': v8_utilities.on_instance(interface, attribute),
         'on_interface': v8_utilities.on_interface(interface, attribute),
         'on_prototype': v8_utilities.on_prototype(interface, attribute),
@@ -579,7 +579,7 @@ def property_attributes(interface, attribute):
     if ('NotEnumerable' in extended_attributes or
             is_constructor_attribute(attribute)):
         property_attributes_list.append('v8::DontEnum')
-    if is_unforgeable(interface, attribute):
+    if is_unforgeable(attribute):
         property_attributes_list.append('v8::DontDelete')
     if not is_writable(attribute):
         property_attributes_list.append('v8::ReadOnly')

third_party/blink/renderer/bindings/scripts/v8_methods.py

@@ -220,7 +220,7 @@ def method_context(interface, method, is_visible=True):
         'is_per_world_bindings': 'PerWorldBindings' in extended_attributes,
         'is_raises_exception': is_raises_exception,
         'is_static': is_static,
-        'is_unforgeable': is_unforgeable(interface, method),
+        'is_unforgeable': is_unforgeable(method),
         'is_variadic': arguments and arguments[-1].is_variadic,
         'measure_as': v8_utilities.measure_as(method, interface),  # [MeasureAs]
         'name': name,
@@ -450,7 +450,7 @@ def property_attributes(interface, method):
     property_attributes_list = []
     if 'NotEnumerable' in extended_attributes:
         property_attributes_list.append('v8::DontEnum')
-    if is_unforgeable(interface, method):
+    if is_unforgeable(method):
         property_attributes_list.append('v8::ReadOnly')
         property_attributes_list.append('v8::DontDelete')
     return property_attributes_list

third_party/blink/renderer/bindings/scripts/v8_utilities.py

@@ -449,10 +449,8 @@ def runtime_enabled_feature_name(definition_or_member):
 
 
 # [Unforgeable]
-def is_unforgeable(interface, member):
-    return (('Unforgeable' in interface.extended_attributes or
-             'Unforgeable' in member.extended_attributes) and
-            not member.is_static)
+def is_unforgeable(member):
+    return 'Unforgeable' in member.extended_attributes
 
 
 # [LegacyInterfaceTypeChecking]
@@ -485,8 +483,7 @@ def on_instance(interface, member):
 
     if ('PrimaryGlobal' in interface.extended_attributes or
             'Global' in interface.extended_attributes or
-            'Unforgeable' in member.extended_attributes or
-            'Unforgeable' in interface.extended_attributes):
+            'Unforgeable' in member.extended_attributes):
         return True
     return False
 
@@ -517,8 +514,7 @@ def on_prototype(interface, member):
 
     if ('PrimaryGlobal' in interface.extended_attributes or
             'Global' in interface.extended_attributes or
-            'Unforgeable' in member.extended_attributes or
-            'Unforgeable' in interface.extended_attributes):
+            'Unforgeable' in member.extended_attributes):
         return False
     return True