Remove unused SpellChecker::CancelCheck

The function is dead for pretty long time. So this CL removes it.

Bug: 924616
Change-Id: I33d0d377add5f6ada2a4e25fab6d086561874d86
Reviewed-on: https://chromium-review.googlesource.com/c/1436674
Auto-Submit: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#626129}

third_party/blink/renderer/core/editing/spellcheck/spell_checker.cc

@@ -595,10 +595,6 @@ void SpellChecker::RemoveMarkers(const EphemeralRange& range,
   GetFrame().GetDocument()->Markers().RemoveMarkersInRange(range, marker_types);
 }
 
-void SpellChecker::CancelCheck() {
-  spell_check_requester_->CancelCheck();
-}
-
 void SpellChecker::DidAttachDocument(Document* document) {
   idle_spell_check_controller_->DidAttachDocument(document);
 }

third_party/blink/renderer/core/editing/spellcheck/spell_checker.h

@@ -81,7 +81,6 @@ class CORE_EXPORT SpellChecker final : public GarbageCollected<SpellChecker> {
   bool SelectionStartHasMarkerFor(DocumentMarker::MarkerType,
                                   int from,
                                   int length) const;
-  void CancelCheck();
 
   // Exposed for testing and idle time spell checker
   SpellCheckRequester& GetSpellCheckRequester() const {