Implement WebIDL codegen for ByteString.

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

@@ -687,6 +687,24 @@ def getJSToNativeConversionTemplate(type, descriptorProvider, failureCode=None,
 
         return handleOptional(getConversionCode(), CGGeneric(declType), isOptional)
 
+    if type.isByteString():
+        assert not isEnforceRange and not isClamp
+
+        conversionCode = (
+            "match FromJSValConvertible::from_jsval(cx, ${val}, ()) {\n"
+            "  Ok(strval) => strval,\n"
+            "  Err(_) => { %s },\n"
+            "}" % exceptionCode)
+
+        declType = CGGeneric("ByteString")
+        if type.nullable():
+            declType = CGWrapper(declType, pre="Option<", post=">")
+            conversionCode = handleDefaultNull(conversionCode, "None")
+        else:
+            assert defaultValue is None
+
+        return handleOptional(conversionCode, declType, isOptional)
+
     if type.isEnum():
         assert not isEnforceRange and not isClamp
 
@@ -996,6 +1014,11 @@ def getRetvalDeclarationForType(returnType, descriptorProvider):
         if returnType.nullable():
             result = CGWrapper(result, pre="Option<", post=">")
         return result
+    if returnType.isByteString():
+        result = CGGeneric("ByteString")
+        if returnType.nullable():
+            result = CGWrapper(result, pre="Option<", post=">")
+        return result
     if returnType.isEnum():
         result = CGGeneric(returnType.unroll().inner.identifier.name)
         if returnType.nullable():
@@ -4283,11 +4306,12 @@ class CGBindingRoot(CGThing):
             'dom::bindings::error::{FailureUnknown, Fallible, Error, ErrorResult}',
             'dom::bindings::error::{throw_method_failed_with_details}',
             'dom::bindings::error::throw_type_error',
-            'script_task::JSPageInfo',
             'dom::bindings::proxyhandler',
             'dom::bindings::proxyhandler::{_obj_toString, defineProperty}',
             'dom::bindings::proxyhandler::{FillPropertyDescriptor, GetExpandoObject}',
             'dom::bindings::proxyhandler::{getPropertyDescriptor}',
+            'dom::bindings::str::ByteString',
+            'script_task::JSPageInfo',
             'libc',
             'servo_util::str::DOMString',
             'servo_util::vec::zip_copies',