Move the exception logic to the AudioNode creator

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

Index: third_party/WebKit/Source/modules/webaudio/PannerNode.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/PannerNode.cpp b/third_party/WebKit/Source/modules/webaudio/PannerNode.cpp
index ad21f7a0e81952fb79e562246e2ed20cc169aa67..1b9276b0bf736d6812f7572156da8cb7fa001475 100644
--- a/third_party/WebKit/Source/modules/webaudio/PannerNode.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/PannerNode.cpp
@@ -494,15 +494,22 @@ void PannerHandler::setChannelCountMode(const String& mode, ExceptionState& exce
 
 // ----------------------------------------------------------------
 
-PannerNode::PannerNode(AbstractAudioContext& context, float sampelRate)
+PannerNode::PannerNode(AbstractAudioContext& context)
     : AudioNode(context)
 {
-    setHandler(PannerHandler::create(*this, sampelRate));
+    setHandler(PannerHandler::create(*this, context.sampleRate()));
 }
 
-PannerNode* PannerNode::create(AbstractAudioContext& context, float sampleRate)
+PannerNode* PannerNode::create(AbstractAudioContext& context, ExceptionState& exceptionState)
 {
-    return new PannerNode(context, sampleRate);
+    DCHECK(isMainThread());
+
+    if (context.isContextClosed()) {
+        context.throwExceptionForClosedState(exceptionState);
+        return nullptr;
+    }
+
+    return new PannerNode(context);
 }
 
 PannerHandler& PannerNode::pannerHandler() const