events: Update key-event handlers to not return EventResult.

ash/wm/event_rewriter_event_filter.cc

Index: ash/wm/event_rewriter_event_filter.cc
diff --git a/ash/wm/event_rewriter_event_filter.cc b/ash/wm/event_rewriter_event_filter.cc
index fc36c0cb58909905de3fbc129ea563213e8d4c1d..81ed7e58853b49668268b7ceb62c7800f95759d4 100644
--- a/ash/wm/event_rewriter_event_filter.cc
+++ b/ash/wm/event_rewriter_event_filter.cc
@@ -20,25 +20,23 @@ void EventRewriterEventFilter::SetEventRewriterDelegate(
   delegate_.swap(delegate);
 }
 
-ui::EventResult EventRewriterEventFilter::OnKeyEvent(ui::KeyEvent* event) {
+void EventRewriterEventFilter::OnKeyEvent(ui::KeyEvent* event) {
   if (!delegate_.get())
-    return ui::ER_UNHANDLED;
+    return;
 
   // Do not consume a translated key event which is generated by an IME.
   if (event->type() == ui::ET_TRANSLATED_KEY_PRESS ||
       event->type() == ui::ET_TRANSLATED_KEY_RELEASE) {
-    return ui::ER_UNHANDLED;
+    return;
   }
 
   switch (delegate_->RewriteOrFilterKeyEvent(event)) {
     case EventRewriterDelegate::ACTION_REWRITE_EVENT:
-      return ui::ER_UNHANDLED;
+      break;
     case EventRewriterDelegate::ACTION_DROP_EVENT:
-      return ui::ER_CONSUMED;
+      event->StopPropagation();
+      break;
   }
-
-  NOTREACHED();
-  return ui::ER_UNHANDLED;
 }
 
 ui::EventResult EventRewriterEventFilter::OnMouseEvent(ui::MouseEvent* event) {