Add missing fling_curve* entries to GN events targets.

ui/events/BUILD.gn

Index: ui/events/BUILD.gn
diff --git a/ui/events/BUILD.gn b/ui/events/BUILD.gn
index 99372b33ef36c5caa2da80ac481a3d6a45e21daa..48cddeef492f2e2eda823d9f026729af1aefb059 100644
--- a/ui/events/BUILD.gn
+++ b/ui/events/BUILD.gn
@@ -25,6 +25,8 @@ component("events_base") {
     "events_base_export.h",
     "gesture_event_details.cc",
     "gesture_event_details.h",
+    "gestures/fling_curve.cc",
+    "gestures/fling_curve.h",
     "gestures/gesture_configuration.cc",
     "gestures/gesture_configuration.h",
     "keycodes/keyboard_code_conversion.cc",
@@ -278,6 +280,7 @@ test("events_unittests") {
     "gesture_detection/motion_event_generic_unittest.cc",
     "gesture_detection/touch_disposition_gesture_filter_unittest.cc",
     "gesture_detection/velocity_tracker_unittest.cc",
+    "gestures/fling_curve_unittest.cc",
     "keycodes/dom4/keycode_converter_unittest.cc",
     "latency_info_unittest.cc",
     "platform/platform_event_source_unittest.cc",