Implement AudioWorkletProcessor interface

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
new file mode 100644
index 0000000000000000000000000000000000000000..d0f17fe3aff94a86f3073cc5b50ca343c2fd7cdf
--- /dev/null
+++ b/third_party/WebKit/Source/modules/webaudio/AudioWorkletProcessor.cpp
@@ -0,0 +1,50 @@
+// 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 implicitly when an instance of

[Raymond Toy, 2017/03/17 16:45:32]

How is it called "implicitly"?

[hongchan, 2017/03/20 17:03:32]

I tried to explain the procedure in he design doc:
https://docs.google.com/document/d/1RHPNJ7Dz5hFebPCG9KI_wG4pb1EnKRmzzE7Io1Lkr...

+// |AudioWorkletNode| gets created by user-supplied JS code in the main thread.
+// This factory must not be called by user in |AudioWorkletGlobalScope|.

[Raymond Toy, 2017/03/17 16:45:32]

Anyway to check that it's being called the user in AudioWorkletGlobalScope? 
That would be great.

[hongchan, 2017/03/20 17:03:32]

DCHECK(globalScope) is the best I can do here.

+AudioWorkletProcessor* AudioWorkletProcessor::create(
+    AudioWorkletGlobalScope* globalScope,
+    const String& name) {
+  DCHECK(!isMainThread());

[Raymond Toy, 2017/03/17 16:45:32]

CHECK(globalScope)?

[hongchan, 2017/03/20 17:03:32]

Done.

+  return new AudioWorkletProcessor(globalScope, name);

[Raymond Toy, 2017/03/17 16:45:32]

Is it an error to return nullptr? Is it up to the callers to verify this?

[hongchan, 2017/03/20 17:03:32]

Checks are done by AudioWorkletGlobalScope. This AudioWorkletProcessor is
basically a thin wrapper for the class definition.

+}
+
+AudioWorkletProcessor::AudioWorkletProcessor(
+    AudioWorkletGlobalScope* globalScope,
+    const String& name)
+    : m_globalScope(globalScope), m_name(name) {}

[Raymond Toy, 2017/03/17 16:45:32]

CHECK(globalScope)? I assume things aren't going to work if globalScope is null
for any reason.

[hongchan, 2017/03/20 17:03:32]

The static factory already checks |globalScope| and the constructor is private
as well.

+
+AudioWorkletProcessor::~AudioWorkletProcessor() {}
+
+void AudioWorkletProcessor::setInstance(v8::Isolate* isolate,
+                                        v8::Local<v8::Object> instance) {
+  DCHECK(m_globalScope->isContextThread());
+  m_instance.set(isolate, instance);
+}
+
+v8::Local<v8::Object> AudioWorkletProcessor::instanceLocal(
+    v8::Isolate* isolate) {
+  DCHECK(m_globalScope->isContextThread());
+  return m_instance.newLocal(isolate);
+}
+
+void AudioWorkletProcessor::process(AudioBuffer* inputBuffer,
+                                    AudioBuffer* outputBuffer) {
+  DCHECK(m_globalScope->isContextThread());
+  m_globalScope->process(this, inputBuffer, outputBuffer);
+}
+
+DEFINE_TRACE(AudioWorkletProcessor) {
+  visitor->trace(m_globalScope);
+}
+
+}  // namespace blink