Fix clone() behavior on CanvasCaptureMediaStreamTrack

third_party/WebKit/Source/modules/mediacapturefromelement/CanvasCaptureMediaStreamTrack.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "modules/mediacapturefromelement/CanvasCaptureMediaStreamTrack.h"
 
 #include "core/html/HTMLCanvasElement.h"
 #include "modules/mediacapturefromelement/AutoCanvasDrawListener.h"
 #include "platform/NotImplemented.h"
+#include "platform/mediastream/MediaStreamCenter.h"
 
 namespace blink {
 
 CanvasCaptureMediaStreamTrack* CanvasCaptureMediaStreamTrack::create(MediaStreamComponent* component, PassRefPtrWillBeRawPtr<HTMLCanvasElement> element, const PassOwnPtr<WebCanvasCaptureHandler> handler)
 {
     return new CanvasCaptureMediaStreamTrack(component, element, handler);
 }
 
 HTMLCanvasElement* CanvasCaptureMediaStreamTrack::canvas() const
 {
     return m_canvasElement.get();
 }
 
 void CanvasCaptureMediaStreamTrack::requestFrame()
 {
     notImplemented();
     return;
 }
 
+CanvasCaptureMediaStreamTrack* CanvasCaptureMediaStreamTrack::clone(ExecutionContext* context)
+{
+    MediaStreamComponent* clonedComponent = MediaStreamComponent::create(component()->source());
+    CanvasCaptureMediaStreamTrack* clonedTrack = new CanvasCaptureMediaStreamTrack(*this, clonedComponent);
+    MediaStreamCenter::instance().didCreateMediaStreamTrack(clonedComponent);
+    return clonedTrack;
+}
+
 DEFINE_TRACE(CanvasCaptureMediaStreamTrack)
 {
     visitor->trace(m_canvasElement);
     visitor->trace(m_drawListener);
     MediaStreamTrack::trace(visitor);
 }
 
+CanvasCaptureMediaStreamTrack::CanvasCaptureMediaStreamTrack(const CanvasCaptureMediaStreamTrack& track, MediaStreamComponent* component)
+    :MediaStreamTrack(track.m_canvasElement->executionContext(), component)
+    , m_canvasElement(track.m_canvasElement)
+    , m_drawListener(track.m_drawListener)
+{
+    suspendIfNeeded();
+    m_canvasElement->addListener(m_drawListener.get());
+}
+
 CanvasCaptureMediaStreamTrack::CanvasCaptureMediaStreamTrack(MediaStreamComponent* component, PassRefPtrWillBeRawPtr<HTMLCanvasElement> element, const PassOwnPtr<WebCanvasCaptureHandler> handler)
     : MediaStreamTrack(element->executionContext(), component)
     , m_canvasElement(element)
 {
     suspendIfNeeded();
     m_drawListener = AutoCanvasDrawListener::create(handler);
     m_canvasElement->addListener(m_drawListener.get());
 }
 
 } // namespace blink