MacViews: Implement Force Touch/Mac dictionary lookup for Textfields.

ui/views/view.cc

Index: ui/views/view.cc
diff --git a/ui/views/view.cc b/ui/views/view.cc
index 847f807f356b944d275b238348bdb7db88b62032..29ea422f13f2194eb2e5de7c956b0e1982a9d137 100644
--- a/ui/views/view.cc
+++ b/ui/views/view.cc
@@ -1080,6 +1080,10 @@ ViewTargeter* View::GetEffectiveViewTargeter() const {
   return view_targeter;
 }
 
+LookupWordClient* View::GetLookupWordClient() {
+  return nullptr;
+}
+
 bool View::CanAcceptEvent(const ui::Event& event) {
   return IsDrawn();
 }