Lazy initialization of the rendering thread in OfflineAudioContext

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

Index: third_party/WebKit/Source/modules/webaudio/OfflineAudioContext.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/OfflineAudioContext.cpp b/third_party/WebKit/Source/modules/webaudio/OfflineAudioContext.cpp
index 1b310a9db147308bf597838d58b70511ed36e1ad..8bb00da84edd7ae0f69b19191b0eb77ae198476e 100644
--- a/third_party/WebKit/Source/modules/webaudio/OfflineAudioContext.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/OfflineAudioContext.cpp
@@ -212,6 +212,7 @@ ScriptPromise OfflineAudioContext::startOfflineRendering(
   // Start rendering and return the promise.
   is_rendering_started_ = true;
   SetContextState(kRunning);
+  DestinationHandler().InitializeOfflineRenderThread();
   DestinationHandler().StartRendering();
 
   return complete_resolver_->Promise();
@@ -230,13 +231,6 @@ ScriptPromise OfflineAudioContext::suspendContext(ScriptState* script_state,
   ScriptPromiseResolver* resolver = ScriptPromiseResolver::Create(script_state);
   ScriptPromise promise = resolver->Promise();
 
-  // The render thread does not exist; reject the promise.
-  if (!DestinationHandler().OfflineRenderThread()) {

[Raymond Toy, 2017/05/23 17:05:01]

What happened before if I try to suspend a context that has already finished
rendering?  What happens with this CL?

[hongchan, 2017/05/23 18:10:38]

A good catch. My mistake. I forgot to revert this back.

[Raymond Toy, 2017/05/23 18:14:41]

In that case, we want to include a test for this with this CL.

-    resolver->Reject(DOMException::Create(kInvalidStateError,
-                                          "the rendering is already finished"));
-    return promise;
-  }
-
   // The specified suspend time is negative; reject the promise.
   if (when < 0) {
     resolver->Reject(DOMException::Create(