exo: Replace fling cancel with generic zero distance scroll

components/exo/pointer.h

Index: components/exo/pointer.h
diff --git a/components/exo/pointer.h b/components/exo/pointer.h
index 8cfdbab86362c4f218a007b544b7e30dc5ce651b..86260affc2ab5288e48e4f5ad3e69321068c1173 100644
--- a/components/exo/pointer.h
+++ b/components/exo/pointer.h
@@ -11,6 +11,7 @@
 #include "components/exo/surface_delegate.h"
 #include "components/exo/surface_observer.h"
 #include "components/exo/wm_helper.h"
+#include "ui/events/event_constants.h"
 #include "ui/events/event_handler.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/point_f.h"
@@ -110,6 +111,9 @@ class Pointer : public ui::EventHandler,
   // True if the pointer is controlled via direct input.
   bool is_direct_input_ = false;
 
+  // Last received event type.
+  ui::EventType last_event_type_ = ui::ET_UNKNOWN;
+
   DISALLOW_COPY_AND_ASSIGN(Pointer);
 };