exo: Select cursor capture scale at run time

components/exo/pointer.h

Index: components/exo/pointer.h
diff --git a/components/exo/pointer.h b/components/exo/pointer.h
index 571743c818389d410750eadcd9ae89dd3e47ed55..74c5b976e3dc948c41eea5648e1903e966326810 100644
--- a/components/exo/pointer.h
+++ b/components/exo/pointer.h
@@ -111,6 +111,10 @@ class Pointer : public ui::EventHandler,
   // The current cursor.
   ui::Cursor cursor_;
 
+  // Scale at which cursor snapshot is captured. The resulting bitmap is scaled
+  // on displays whose DSF does not match this scale.
+  float capture_scale_;
+
   // Source used for cursor capture copy output requests.
   const base::UnguessableToken cursor_capture_source_id_;