Implement ReadableStream as a V8 extra

Source/bindings/scripts/v8_types.py

Index: Source/bindings/scripts/v8_types.py
diff --git a/Source/bindings/scripts/v8_types.py b/Source/bindings/scripts/v8_types.py
index e4b45c79266e229ef91bd212ca783539a7d67883..ec7fcfcd4ab38f7da3e0fd20ede62b047868c881 100644
--- a/Source/bindings/scripts/v8_types.py
+++ b/Source/bindings/scripts/v8_types.py
@@ -111,6 +111,7 @@ CPP_SPECIAL_CONVERSION_RULES = {
     'EventHandler': 'EventListener*',
     'NodeFilter': 'RefPtrWillBeRawPtr<NodeFilter>',
     'Promise': 'ScriptPromise',
+    'ReadableStream2': 'ScriptReadableStream',
     'ScriptValue': 'ScriptValue',
     # FIXME: Eliminate custom bindings for XPathNSResolver  http://crbug.com/345529
     'XPathNSResolver': 'RawPtr<XPathNSResolver>',
@@ -362,6 +363,7 @@ INCLUDES_FOR_TYPE = {
                      'core/dom/StaticNodeList.h',
                      'core/html/LabelsNodeList.h']),
     'Promise': set(['bindings/core/v8/ScriptPromise.h']),
+    'ReadableStream2': set(['core/streams/ScriptReadableStream.h']),
     'SerializedScriptValue': set(['bindings/core/v8/SerializedScriptValue.h',
                                   'bindings/core/v8/SerializedScriptValueFactory.h']),
     'ScriptValue': set(['bindings/core/v8/ScriptValue.h']),
@@ -697,7 +699,7 @@ IdlTypeBase.preprocessed_type = property(preprocess_idl_type)
 def preprocess_idl_type_and_value(idl_type, cpp_value, extended_attributes):
     """Returns IDL type and value, with preliminary type conversions applied."""
     idl_type = idl_type.preprocessed_type
-    if idl_type.name == 'Promise':
+    if idl_type.name == 'Promise' or idl_type.name == 'ReadableStream2':
         idl_type = IdlType('ScriptValue')
     if idl_type.base_type in ['long long', 'unsigned long long']:
         # long long and unsigned long long are not representable in ECMAScript;