Use wrapper tracing for worklets.

third_party/WebKit/Source/modules/webaudio/AudioWorkletProcessor.cpp

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/webaudio/AudioWorkletProcessor.h"
 
 #include "modules/webaudio/AudioWorkletGlobalScope.h"
 
 namespace blink {
 
 // This static factory should be called after an instance of |AudioWorkletNode|
 // gets created by user-supplied JS code in the main thread. This factory must
 // not be called by user in |AudioWorkletGlobalScope|.
 AudioWorkletProcessor* AudioWorkletProcessor::Create(
     AudioWorkletGlobalScope* global_scope,
     const String& name) {
   DCHECK(!IsMainThread());
   DCHECK(global_scope);
   return new AudioWorkletProcessor(global_scope, name);
 }
 
 AudioWorkletProcessor::AudioWorkletProcessor(
     AudioWorkletGlobalScope* global_scope,
     const String& name)
-    : global_scope_(global_scope), name_(name) {}
+    : global_scope_(global_scope), name_(name), instance_(this) {}
 
 AudioWorkletProcessor::~AudioWorkletProcessor() {}
 
 void AudioWorkletProcessor::SetInstance(v8::Isolate* isolate,
                                         v8::Local<v8::Object> instance) {
   DCHECK(global_scope_->IsContextThread());
   instance_.Set(isolate, instance);
 }
 
 v8::Local<v8::Object> AudioWorkletProcessor::InstanceLocal(
     v8::Isolate* isolate) {
   DCHECK(global_scope_->IsContextThread());
   return instance_.NewLocal(isolate);
 }
 
 void AudioWorkletProcessor::Process(AudioBuffer* input_buffer,
                                     AudioBuffer* output_buffer) {
   DCHECK(global_scope_->IsContextThread());
   global_scope_->Process(this, input_buffer, output_buffer);
 }
 
 DEFINE_TRACE(AudioWorkletProcessor) {
   visitor->Trace(global_scope_);
 }
 
+DEFINE_TRACE_WRAPPERS(AudioWorkletProcessor) {
+  visitor->TraceWrappers(instance_.Cast<v8::Value>());
+}
+
 }  // namespace blink