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 a8fdc1741b6ca79c51d50ab82c3b04d7dea1aca2..fcc09a3bf16d6f4aac4332fabed7c4a639382c51 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 "platform/geometry/FloatRect.h"
 #include "platform/geometry/IntSize.h"
@@ -60,7 +61,7 @@ class ImageBufferSurface;
 class ImageData;
 class IntSize;
 
-class CORE_EXPORT HTMLCanvasElement final : public HTMLElement, public DocumentVisibilityObserver, public CanvasImageSource, public ImageBufferClient {
+class CORE_EXPORT HTMLCanvasElement : public HTMLElement, public DocumentVisibilityObserver, public CanvasImageSource, public ImageBufferClient {
     DEFINE_WRAPPERTYPEINFO();
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(HTMLCanvasElement);
 public:
@@ -101,6 +102,10 @@ 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&);
 
@@ -193,9 +198,13 @@ 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;