Implement AudioWorkletProcessor interface

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/AudioBuffer.h"
+#include "modules/webaudio/AudioWorkletGlobalScope.h"
+#include "modules/webaudio/AudioWorkletProcessorDefinition.h"
+
+namespace blink {
+
+AudioWorkletProcessor* AudioWorkletProcessor::create(
+    const String& name,
+    AudioWorkletGlobalScope* globalScope) {
+  AudioWorkletProcessorDefinition* definition =
+      globalScope->findDefinition(name);
+
+  if (!definition)
+    return nullptr;

[nhiroki, 2017/03/06 10:08:44]

It looks strange that create() returns a nullptr. How about checking
|findDefinition()| in the caller and then passing a valid |definition| to
create() instead of |globalScope|?

[hongchan, 2017/03/06 20:06:12]

Ah, that's right. This method does not get called by user-supplied JS code. Thus
it's okay to check the definition in the caller. I was following our WebAudio's
regular constructor pattern.

+
+  return new AudioWorkletProcessor(definition);
+}
+
+AudioWorkletProcessor::AudioWorkletProcessor(
+    AudioWorkletProcessorDefinition* definition)
+    : m_definition(definition) {
+  m_instance = m_definition->createInstance();
+}
+
+AudioWorkletProcessor::~AudioWorkletProcessor() {}
+
+bool AudioWorkletProcessor::process(AudioBuffer* inputBuffer,
+                                    AudioBuffer* outputBuffer) {
+  DCHECK(m_definition);
+  DCHECK(!m_instance.IsEmpty());
+
+  return m_definition->process(m_instance, inputBuffer, outputBuffer);
+}
+
+DEFINE_TRACE(AudioWorkletProcessor) {
+  visitor->trace(m_definition);
+}
+
+}  // namespace blink