diff -r 000000000000 -r 6474c204b198 dom/camera/CameraPreviewMediaStream.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/camera/CameraPreviewMediaStream.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,61 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef DOM_CAMERA_CAMERAPREVIEWMEDIASTREAM_H
+#define DOM_CAMERA_CAMERAPREVIEWMEDIASTREAM_H
+
+#include "VideoFrameContainer.h"
+#include "MediaStreamGraph.h"
+#include "mozilla/Mutex.h"
+
+namespace mozilla {
+
+class CameraPreviewFrameCallback {
+public:
+  virtual void OnNewFrame(const gfxIntSize& aIntrinsicSize, layers::Image* aImage) = 0;
+};
+
+/**
+ * This is a stream for camere preview.
+ *
+ * XXX It is a temporary fix of SourceMediaStream.
+ * A camera preview requests no delay and no buffering stream.
+ * But the SourceMediaStream do not support it.
+ */
+class CameraPreviewMediaStream : public MediaStream
+{
+  typedef mozilla::layers::Image Image;
+
+public:
+  CameraPreviewMediaStream(DOMMediaStream* aWrapper);
+
+  virtual void AddAudioOutput(void* aKey) MOZ_OVERRIDE;
+  virtual void SetAudioOutputVolume(void* aKey, float aVolume) MOZ_OVERRIDE;
+  virtual void RemoveAudioOutput(void* aKey) MOZ_OVERRIDE;
+  virtual void AddVideoOutput(VideoFrameContainer* aContainer) MOZ_OVERRIDE;
+  virtual void RemoveVideoOutput(VideoFrameContainer* aContainer) MOZ_OVERRIDE;
+  virtual void ChangeExplicitBlockerCount(int32_t aDelta) MOZ_OVERRIDE;
+  virtual void AddListener(MediaStreamListener* aListener) MOZ_OVERRIDE;
+  virtual void RemoveListener(MediaStreamListener* aListener) MOZ_OVERRIDE;
+  virtual void Destroy();
+
+  // Call these on any thread.
+  void SetCurrentFrame(const gfxIntSize& aIntrinsicSize, Image* aImage);
+  void ClearCurrentFrame();
+
+  void SetFrameCallback(CameraPreviewFrameCallback* aCallback) {
+    mFrameCallback = aCallback;
+  }
+
+protected:
+  // mMutex protects all the class' fields.
+  // This class is not registered to MediaStreamGraph.
+  // It needs to protect all the fields.
+  Mutex mMutex;
+  CameraPreviewFrameCallback* mFrameCallback;
+};
+
+}
+
+#endif // DOM_CAMERA_CAMERAPREVIEWMEDIASTREAM_H