CefRenderHandlerStartDragging Method

Called when the user starts dragging content in the web view. Contextual information about the dragged content is supplied by |drag_data|. (|x|, |y|) is the drag start location in screen coordinates. OS APIs that run a system message loop may be used within the StartDragging call. Return false to abort the drag operation. Don't call any of CefBrowserHost::DragSource*Ended* methods after returning false. Return true to handle the drag operation. Call CefBrowserHost::DragSourceEndedAt and DragSourceSystemDragEnded either synchronously or asynchronously to inform the web view that the drag operation has ended.

protected virtual bool StartDragging(
	CefBrowser browser,
	CefDragData dragData,
	CefDragOperationsMask allowedOps,
	int x,
	int y
)