IDL compiler: [RaisesException] interface type attribute

Source/bindings/scripts/unstable/v8_attributes.py

Index: Source/bindings/scripts/unstable/v8_attributes.py
diff --git a/Source/bindings/scripts/unstable/v8_attributes.py b/Source/bindings/scripts/unstable/v8_attributes.py
index 56b14963983a8b4deef7524fcc81d2b27460dde3..9967cbd82fe6a730cc7770841299042ec5e4c66d 100644
--- a/Source/bindings/scripts/unstable/v8_attributes.py
+++ b/Source/bindings/scripts/unstable/v8_attributes.py
@@ -140,22 +140,28 @@ def generate_getter(interface, attribute, contents):
     cpp_value = getter_expression(interface, attribute, contents)
     # Normally we can inline the function call into the return statement to
     # avoid the overhead of using a Ref<> temporary, but for some cases
-    # (nullable types, EventHandler, [CachedAttribute], or if there are
-    # exceptions), we need to use a local variable.
+    # (nullable types, [RaisesException], [CachedAttribute], and EventHandler)
+    # we need to use a local variable.
     # FIXME: check if compilers are smart enough to inline this, and if so,
     # always use a local variable (for readability and CG simplicity).
-    if (attribute.is_nullable or
-        idl_type == 'EventHandler' or
-        'CachedAttribute' in extended_attributes or
-        contents['is_getter_raises_exception']):
+    if idl_type == 'EventHandler':
+        contents['cpp_value_original'] = cpp_value
+        cpp_rvalue = cpp_value = 'jsValue'
+    elif (attribute.is_nullable or
+          contents['is_getter_raises_exception'] or
+          'CachedAttribute' in extended_attributes):
         contents['cpp_value_original'] = cpp_value
-        cpp_value = 'jsValue'
+        cpp_rvalue = cpp_value = 'jsValue'
+        if v8_types.is_interface_type(idl_type):
+            cpp_rvalue += '.release()'
+    else:
+        cpp_rvalue = cpp_value
 
     if contents['is_keep_alive_for_gc']:
         v8_set_return_value_statement = 'v8SetReturnValue(info, wrapper)'
         includes.add('bindings/v8/V8HiddenPropertyName.h')
     else:
-        v8_set_return_value_statement = v8_types.v8_set_return_value(idl_type, cpp_value, extended_attributes=extended_attributes, script_wrappable='imp')
+        v8_set_return_value_statement = v8_types.v8_set_return_value(idl_type, cpp_rvalue, extended_attributes=extended_attributes, script_wrappable='imp')
 
     contents.update({
         'cpp_value': cpp_value,