Basic use implementation for MediaStream from Canvas: captureStream()

third_party/WebKit/Source/core/html/HTMLCanvasElement.h

Index: third_party/WebKit/Source/core/html/HTMLCanvasElement.h
diff --git a/third_party/WebKit/Source/core/html/HTMLCanvasElement.h b/third_party/WebKit/Source/core/html/HTMLCanvasElement.h
index f208f37cd8c8b58d3b37059210374440d256c221..73e5471cc1a85c2cd84b5845cb67a49189a8a59f 100644
--- a/third_party/WebKit/Source/core/html/HTMLCanvasElement.h
+++ b/third_party/WebKit/Source/core/html/HTMLCanvasElement.h
@@ -36,6 +36,7 @@
 #include "core/dom/DocumentVisibilityObserver.h"
 #include "core/fileapi/FileCallback.h"
 #include "core/html/HTMLElement.h"
+#include "core/html/canvas/CanvasDrawListener.h"
 #include "core/html/canvas/CanvasImageSource.h"
 #include "core/imagebitmap/ImageBitmapSource.h"
 #include "platform/geometry/FloatRect.h"
@@ -102,6 +103,10 @@ public:
     void toBlob(FileCallback*, const String& mimeType, const ScriptValue& qualityArgument, ExceptionState&);
     void toBlob(FileCallback* callback, const String& mimeType, ExceptionState& exceptionState) { return toBlob(callback, mimeType, ScriptValue(), exceptionState); }
 
+    // Used for canvas capture.
+    void addListener(CanvasDrawListener*);
+    void removeListener(CanvasDrawListener*);
+
     // Used for rendering
     void didDraw(const FloatRect&);
 
@@ -198,9 +203,13 @@ private:
 
     bool paintsIntoCanvasBuffer() const;
 
+    void notifyListenersCanvasChanged();
+
     ImageData* toImageData(SourceDrawingBuffer) const;
     String toDataURLInternal(const String& mimeType, const double& quality, SourceDrawingBuffer) const;
 
+    PersistentHeapHashSetWillBeHeapHashSet<WeakMember<CanvasDrawListener>> m_listeners;
+
     IntSize m_size;
 
     OwnPtrWillBeMember<CanvasRenderingContext> m_context;