Use wrapper tracing for worklets.

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

Index: third_party/WebKit/Source/modules/webaudio/AudioWorkletProcessor.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/AudioWorkletProcessor.cpp b/third_party/WebKit/Source/modules/webaudio/AudioWorkletProcessor.cpp
index 0ed47cb54a25cad2af8c981292db3928256c7f38..3a43f7d6f0016030a57e5738f48877629dc3c18f 100644
--- a/third_party/WebKit/Source/modules/webaudio/AudioWorkletProcessor.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AudioWorkletProcessor.cpp
@@ -22,7 +22,7 @@ AudioWorkletProcessor* AudioWorkletProcessor::Create(
 AudioWorkletProcessor::AudioWorkletProcessor(
     AudioWorkletGlobalScope* global_scope,
     const String& name)
-    : global_scope_(global_scope), name_(name) {}
+    : global_scope_(global_scope), name_(name), instance_(this) {}
 
 AudioWorkletProcessor::~AudioWorkletProcessor() {}
 
@@ -48,4 +48,8 @@ DEFINE_TRACE(AudioWorkletProcessor) {
   visitor->Trace(global_scope_);
 }
 
+DEFINE_TRACE_WRAPPERS(AudioWorkletProcessor) {
+  visitor->TraceWrappers(instance_.Cast<v8::Value>());
+}
+
 }  // namespace blink