Basic use implementation for MediaStream from Canvas: captureStream()

third_party/WebKit/Source/modules/mediacapturefromelement/CanvasCaptureMediaStream.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/CanvasCaptureMediaStream.h"
+
+#include "core/html/HTMLCanvasElement.h"
+#include "modules/mediacapturefromelement/AutoCanvasDrawListener.h"
+#include "platform/NotImplemented.h"
+#include "public/platform/WebMediaStream.h"
+#include "public/platform/WebMediaStreamSource.h"
+#include "public/platform/WebMediaStreamTrack.h"
+
+namespace blink {
+
+CanvasCaptureMediaStream::~CanvasCaptureMediaStream()
+{
+    m_canvasElement->removeListener(m_drawListener.get());

[peria, 2015/11/24 05:50:22]

Remove this line.

As a basic rule, we cannot touch Member pointers in destructors.
And if m_drawListener dies with this CanvasCaptureMediaStream,
it will be unregistered from m_canvasElement->m_listeners in Oilpan's
weak processing.

[emircan, 2015/11/24 22:16:51]

Done.

+}
+
+CanvasCaptureMediaStream* CanvasCaptureMediaStream::create(MediaStreamDescriptor* streamDescriptor, HTMLCanvasElement& element, const PassOwnPtr<WebCanvasCaptureHandler>& handler)
+{
+    return new CanvasCaptureMediaStream(streamDescriptor, element, handler);
+}
+
+HTMLCanvasElement* CanvasCaptureMediaStream::canvas() const
+{
+    return m_canvasElement;
+}
+
+void CanvasCaptureMediaStream::requestFrame()
+{
+    notImplemented();
+    return;
+}
+
+DEFINE_TRACE(CanvasCaptureMediaStream)
+{
+    visitor->trace(m_canvasElement);
+    visitor->trace(m_drawListener);
+    MediaStream::trace(visitor);
+}
+
+CanvasCaptureMediaStream::CanvasCaptureMediaStream(MediaStreamDescriptor* streamDescriptor, HTMLCanvasElement& element, const PassOwnPtr<WebCanvasCaptureHandler>& handler)
+    : MediaStream(element.executionContext(), streamDescriptor)
+    , m_canvasElement(&element)
+{
+    m_drawListener = AutoCanvasDrawListener::create(handler);
+    m_canvasElement->addListener(m_drawListener.get());
+}
+
+} // namespace blink