Repost offline rendering task if GC prevents.

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

Index: third_party/WebKit/Source/modules/webaudio/OfflineAudioDestinationNode.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/OfflineAudioDestinationNode.cpp b/third_party/WebKit/Source/modules/webaudio/OfflineAudioDestinationNode.cpp
index e15549cfc9453e021b4c8eab71a605d00e807af4..eafe4053bb6948bfc5a9ca808171a694ae5ea92b 100644
--- a/third_party/WebKit/Source/modules/webaudio/OfflineAudioDestinationNode.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/OfflineAudioDestinationNode.cpp
@@ -182,8 +182,14 @@ void OfflineAudioDestinationHandler::DoOfflineRendering() {
     // already held, simply delay rendering until the next quantum.
     CrossThreadPersistentRegion::LockScope gc_lock(
         ProcessHeap::GetCrossThreadPersistentRegion(), true);
-    if (!gc_lock.HasLock())
+    if (!gc_lock.HasLock()) {
+      // To ensure that the rendering step eventually happens, repost.
+      render_thread_->GetWebTaskRunner()->PostTask(
+          BLINK_FROM_HERE,
+          Bind(&OfflineAudioDestinationHandler::DoOfflineRendering,
+               WrapPassRefPtr(this)));
       return;
+    }
 
     number_of_channels = render_target_->numberOfChannels();
     destinations.ReserveInitialCapacity(number_of_channels);