Introduce [Abstract] to mark non-leaf interfaces

Some interfaces like Node, CharacterData and HTMLTableCellElement are never
instantiated directly, only their descendant interfaces are. Those are marked
with [Abstract] to set their type_id to None instead of having dummy values
in the TypeId enums.

components/script/dom/bindings/codegen/CodegenRust.py

@@ -1724,7 +1724,7 @@ class CGNamespace(CGWrapper):
 
 def EventTargetEnum(desc):
     protochain = desc.prototypeChain
-    if protochain[0] != "EventTarget":
+    if protochain[0] != "EventTarget" or desc.interface.getExtendedAttribute("Abstract"):
         return "None"
 
     inner = ""

components/script/dom/bindings/codegen/parser/WebIDL.py

@@ -1357,7 +1357,8 @@ class IDLInterface(IDLObjectWithScope, IDLExposureMixins):
                   identifier == "ChromeOnly" or
                   identifier == "Unforgeable" or
                   identifier == "UnsafeInPrerendering" or
-                  identifier == "LegacyEventInit"):
+                  identifier == "LegacyEventInit" or
+                  identifier == "Abstract"):
                 # Known extended attributes that do not take values
                 if not attr.noArguments():
                     raise WebIDLError("[%s] must take no arguments" % identifier,

components/script/dom/bindings/codegen/parser/abstract.patch

@@ -0,0 +1,12 @@
+--- WebIDL.py
++++ WebIDL.py
+@@ -1357,7 +1357,8 @@ class IDLInterface(IDLObjectWithScope, IDLExposureMixins):
+                   identifier == "ChromeOnly" or
+                   identifier == "Unforgeable" or
+                   identifier == "UnsafeInPrerendering" or
+-                  identifier == "LegacyEventInit"):
++                  identifier == "LegacyEventInit" or
++                  identifier == "Abstract"):
+                 # Known extended attributes that do not take values
+                 if not attr.noArguments():
+                     raise WebIDLError("[%s] must take no arguments" % identifier,

components/script/dom/bindings/codegen/parser/update.sh

@@ -1,3 +1,4 @@
 wget https://mxr.mozilla.org/mozilla-central/source/dom/bindings/parser/WebIDL.py?raw=1 -O WebIDL.py
 patch < external.patch
 patch < module.patch
+patch < abstract.patch