[HTMLCanvasElement.toBlob] Default callback version without scheduler

Source/core/html/HTMLCanvasElement.h

Index: Source/core/html/HTMLCanvasElement.h
diff --git a/Source/core/html/HTMLCanvasElement.h b/Source/core/html/HTMLCanvasElement.h
index 29dad69ba21f9cc0379eaa21318fc9c1216b0522..fd6a7768cf2ce9f151b2cac78823d1ceed329c01 100644
--- a/Source/core/html/HTMLCanvasElement.h
+++ b/Source/core/html/HTMLCanvasElement.h
@@ -33,6 +33,7 @@
 #include "core/CoreExport.h"
 #include "core/dom/Document.h"
 #include "core/dom/DocumentVisibilityObserver.h"
+#include "core/fileapi/FileCallback.h"
 #include "core/html/HTMLElement.h"
 #include "core/html/canvas/CanvasImageSource.h"
 #include "platform/geometry/FloatRect.h"
@@ -113,6 +114,9 @@ public:
     String toDataURL(const String& mimeType, const ScriptValue& qualityArgument, ExceptionState&) const;
     String toDataURL(const String& mimeType, ExceptionState& exceptionState) const { return toDataURL(mimeType, ScriptValue(), exceptionState); }
 
+    void toBlob(FileCallback*, const String& mimeType, const ScriptValue& qualityArgument, ExceptionState&) const;
+    void toBlob(FileCallback* callback, const String& mimeType, ExceptionState& exceptionState) { return toBlob(callback, mimeType, ScriptValue(), exceptionState); }
+
     // Used for rendering
     void didDraw(const FloatRect&);
     void notifyObserversCanvasChanged(const FloatRect&);