Bug 1456946 - Don't call AudioNode::Initialize on an ChannelSplitterNode during construction to avoid throwing. r=achronop

We initialize the channelCountMode and channelInterpretation (that cannot be
changed) appropriately in the C++ ctor, and the channelCount manually as well.

Then we check manually that the options for the channelCountMode, the
channelCount and channelInterpretation have not been passed, or are not
incorrect.

MozReview-Commit-ID: 4YdYfaGqKqn

--HG--
extra : rebase_source : 1133e35b74249f5457d1584601e8d4c64cb154cc

dom/media/webaudio/ChannelSplitterNode.cpp

@@ -82,8 +82,22 @@ ChannelSplitterNode::Create(AudioContext& aAudioContext,
   RefPtr<ChannelSplitterNode> audioNode =
     new ChannelSplitterNode(&aAudioContext, aOptions.mNumberOfOutputs);
 
-  audioNode->Initialize(aOptions, aRv);
-  if (NS_WARN_IF(aRv.Failed())) {
+  // Manually check that the other options are valid, this node has channelCount,
+  // channelCountMode and channelInterpretation constraints: they cannot be
+  // changed from the default.
+  if (aOptions.mChannelCount.WasPassed() &&
+      aOptions.mChannelCount.Value() != audioNode->ChannelCount()) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return nullptr;
+  }
+  if (aOptions.mChannelInterpretation.WasPassed() &&
+      aOptions.mChannelInterpretation.Value() != audioNode->ChannelInterpretationValue()) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return nullptr;
+  }
+  if (aOptions.mChannelCountMode.WasPassed() &&
+      aOptions.mChannelCountMode.Value() != audioNode->ChannelCountModeValue()) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
     return nullptr;
   }