Add constructors for WebAudio nodes

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

Index: third_party/WebKit/Source/modules/webaudio/ChannelMergerNode.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/ChannelMergerNode.cpp b/third_party/WebKit/Source/modules/webaudio/ChannelMergerNode.cpp
index b0b98e2bbcd64854e94ec70fe92f813f575aebc9..4404bd51fa0230140542ac90032fb862baafa623 100644
--- a/third_party/WebKit/Source/modules/webaudio/ChannelMergerNode.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/ChannelMergerNode.cpp
@@ -34,6 +34,7 @@
 #include "modules/webaudio/AudioNodeInput.h"
 #include "modules/webaudio/AudioNodeOutput.h"
 #include "modules/webaudio/BaseAudioContext.h"
+#include "modules/webaudio/ChannelMergerOptions.h"
 
 
 namespace blink {
@@ -158,5 +159,17 @@ ChannelMergerNode* ChannelMergerNode::create(BaseAudioContext& context, unsigned
     return new ChannelMergerNode(context, numberOfInputs);
 }
 
+ChannelMergerNode* ChannelMergerNode::create(BaseAudioContext* context, const ChannelMergerOptions& options, ExceptionState& exceptionState)
+{
+    ChannelMergerNode* node = create(*context, options.numberOfInputs(), exceptionState);
+
+    if (!node)
+        return nullptr;
+
+    node->handleChannelOptions(options, exceptionState);
+
+    return node;
+}
+
 } // namespace blink