postMessage(): transfer allocation costs along with value.

third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl

 {% from 'utilities.cpp.tmpl' import declare_enum_validation_variable, v8_value_to_local_cpp_value %}
 
 {##############################################################################}
 {% macro generate_method(method, world_suffix) %}
 static void {{method.name}}{{method.overload_index}}Method{{world_suffix}}(const v8::FunctionCallbackInfo<v8::Value>& info) {
   {% filter format_remove_duplicates([
       'ExceptionState exceptionState',
       'ScriptState* scriptState = ']) %}
   {% set define_exception_state -%}
   ExceptionState exceptionState(info.GetIsolate(), ExceptionState::ExecutionContext, "{{interface_name}}", "{{method.name}}");
@@ skipping 447 matching lines @@
     if (exceptionState.hadException())
       return;
     // Neuter the original image bitmaps on the sender context.
     SerializedScriptValue::transferImageBitmapContents(info.GetIsolate(), transferableImageBitmaps, exceptionState);
     if (exceptionState.hadException())
       return;
   }
 
   // FIXME: Only pass scriptState/exceptionState if instance really requires it.
   ScriptState* scriptState = ScriptState::current(info.GetIsolate());
-  instance->postMessage(scriptState, message.release(), transferables.messagePorts, exceptionState);
+  instance->postMessage(scriptState, message.get(), transferables.messagePorts, exceptionState);
+  message->unregisterMemoryAllocatedByCurrentScriptContext();
 }
 {% endmacro %}
 
 
 {##############################################################################}
 {% macro method_callback(method, world_suffix) %}
 void {{v8_class_or_partial}}::{{method.name}}MethodCallback{{world_suffix}}(const v8::FunctionCallbackInfo<v8::Value>& info) {
   {% if not method.overloads %}{# Overloaded methods are measured in overload_resolution_method() #}
   {% if method.measure_as %}
   UseCounter::count(currentExecutionContext(info.GetIsolate()), UseCounter::{{method.measure_as('Method')}});
@@ skipping 147 matching lines @@
                           if method.overloads else
                           method.runtime_enabled_feature_name) %}
 const V8DOMConfiguration::MethodConfiguration {{method.name}}MethodConfiguration = {{method_configuration(method)}};
 V8DOMConfiguration::installMethod(isolate, world, v8::Local<v8::Object>(), prototypeObject, interfaceObject, signature, {{method.name}}MethodConfiguration);
 {% endfilter %}{# runtime_enabled() #}
 {% endfilter %}{# exposed() #}
 {% endfilter %}{# secure_context() #}
 {% endfor %}
 {% endif %}
 {%- endmacro %}