Replace source pointer in cc::CopyOutputRequest with a base::UnguessableToken

content/public/browser/render_widget_host_view_frame_subscriber.h

Index: content/public/browser/render_widget_host_view_frame_subscriber.h
diff --git a/content/public/browser/render_widget_host_view_frame_subscriber.h b/content/public/browser/render_widget_host_view_frame_subscriber.h
index 6485c7da64809c1ef4b5c83b3e4c8131ed3b4259..7df037ab2d7c194c40b044c93db65e9f86a12da4 100644
--- a/content/public/browser/render_widget_host_view_frame_subscriber.h
+++ b/content/public/browser/render_widget_host_view_frame_subscriber.h
@@ -7,6 +7,7 @@
 
 #include "base/callback.h"
 #include "base/time/time.h"
+#include "cc/output/copy_output_request.h"
 
 namespace gfx {
 class Rect;
@@ -68,6 +69,8 @@ class RenderWidgetHostViewFrameSubscriber {
                                   base::TimeTicks present_time,
                                   scoped_refptr<media::VideoFrame>* storage,
                                   DeliverFrameCallback* callback) = 0;
+
+  virtual const base::UnguessableToken& GetSourceIdForCopyRequest() = 0;
 };
 
 }  // namespace content