diff --git a/dom/media/webaudio/AudioBuffer.cpp b/dom/media/webaudio/AudioBuffer.cpp
index d3efa5afdcb3..5bee7c701136 100644
--- a/dom/media/webaudio/AudioBuffer.cpp
+++ b/dom/media/webaudio/AudioBuffer.cpp
@@ -248,6 +248,23 @@ AudioBuffer::Create(nsPIDOMWindowInner* aWindow, uint32_t aNumberOfChannels,
   return buffer.forget();
 }
 
+/* static */ already_AddRefed<AudioBuffer>
+AudioBuffer::Create(nsPIDOMWindowInner* aWindow, float aSampleRate,
+                    AudioChunk&& aInitialContents)
+{
+  AudioChunk initialContents = aInitialContents;
+  ErrorResult rv;
+  RefPtr<AudioBuffer> buffer =
+    new AudioBuffer(aWindow, initialContents.ChannelCount(),
+                    initialContents.mDuration, aSampleRate, rv);
+  if (rv.Failed()) {
+    return nullptr;
+  }
+  buffer->mSharedChannels = Move(aInitialContents);
+
+  return buffer.forget();
+}
+
 JSObject*
 AudioBuffer::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
 {
diff --git a/dom/media/webaudio/AudioBuffer.h b/dom/media/webaudio/AudioBuffer.h
index 978c20c1f4c4..a9f65977fc0e 100644
--- a/dom/media/webaudio/AudioBuffer.h
+++ b/dom/media/webaudio/AudioBuffer.h
@@ -54,6 +54,11 @@ public:
                   nullptr, aRv);
   }
 
+  // Non-unit AudioChunk::mVolume is not supported
+  static already_AddRefed<AudioBuffer>
+  Create(nsPIDOMWindowInner* aWindow, float aSampleRate,
+         AudioChunk&& aInitialContents);
+
   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
 
   NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(AudioBuffer)