Revert of mus: Fix event transformation in client code.

ui/aura/window_event_dispatcher.cc

Index: ui/aura/window_event_dispatcher.cc
diff --git a/ui/aura/window_event_dispatcher.cc b/ui/aura/window_event_dispatcher.cc
index ffd17d6dbe69cb1584f87d0e1c625ee0a2b88ec9..d34ad330b94132a61b11b0bb623da676b972620a 100644
--- a/ui/aura/window_event_dispatcher.cc
+++ b/ui/aura/window_event_dispatcher.cc
@@ -87,6 +87,7 @@
       move_hold_count_(0),
       dispatching_held_event_(nullptr),
       observer_manager_(this),
+      transform_events_(true),
       repost_event_factory_(this),
       held_event_factory_(this) {
   ui::GestureRecognizer::Get()->AddGestureEventHelper(this);
@@ -438,8 +439,10 @@
   // The held events are already in |window()|'s coordinate system. So it is
   // not necessary to apply the transform to convert from the host's
   // coordinate system to |window()|'s coordinate system.
-  if (event->IsLocatedEvent() && !is_dispatched_held_event(*event))
+  if (event->IsLocatedEvent() && !is_dispatched_held_event(*event) &&
+      transform_events_) {
     TransformEventForDeviceScaleFactor(static_cast<ui::LocatedEvent*>(event));
+  }
 }
 
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