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 67a12efedb18f4ae457f3afc74bcf01d3dc7bf49..8935c76d12b3dad5fba2db0ea5e3596ad60436f7 100644
--- a/components/exo/pointer.h
+++ b/components/exo/pointer.h
@@ -14,6 +14,7 @@
 #include "components/exo/surface_observer.h"
 #include "components/exo/wm_helper.h"
 #include "ui/base/cursor/cursor.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,
   // Weak pointer factory used for cursor capture callbacks.
   base::WeakPtrFactory<Pointer> cursor_capture_weak_ptr_factory_;
 
+  // Last received event type.
+  ui::EventType last_event_type_ = ui::ET_UNKNOWN;
+
   DISALLOW_COPY_AND_ASSIGN(Pointer);
 };