events: Make sure the unaccelerated scroll deltas get adjusted properly for device-scale-factor.

ui/base/events/event.h

Index: ui/base/events/event.h
===================================================================
--- ui/base/events/event.h	(revision 185345)
+++ ui/base/events/event.h	(working copy)
@@ -655,6 +655,10 @@
   float y_offset_ordinal() const { return y_offset_ordinal_; }
   int finger_count() const { return finger_count_; }
 
+  // Overridden from LocatedEvent.
+  virtual void UpdateForRootTransform(
+      const gfx::Transform& root_transform) OVERRIDE;
+
  private:
   // Potential accelerated offsets.
   float x_offset_;