Only call NOTIMPLEMENTED() for unknown event types, not ignored ones.

Bug: 866988
Change-Id: I91084c1f34049d1b4aafdc2f1095ac30efe45fea
Reviewed-on: https://chromium-review.googlesource.com/1148702Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577973}

ui/events/cocoa/events_mac.mm

@@ -63,7 +63,6 @@ EventType EventTypeFromNative(const PlatformEvent& native_event) {
     case NSEventTypeRotate:
     case NSEventTypeBeginGesture:
     case NSEventTypeEndGesture:
-      NOTIMPLEMENTED() << type;
       break;
     default:
       NOTIMPLEMENTED() << type;