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

ui/views/controls/textfield/textfield.cc

Index: ui/views/controls/textfield/textfield.cc
diff --git a/ui/views/controls/textfield/textfield.cc b/ui/views/controls/textfield/textfield.cc
index 14736697771bda755ab2e7e08f2ad70cc1fee919..c3addec5219742c281afe883dbb4409e6f7b2151 100644
--- a/ui/views/controls/textfield/textfield.cc
+++ b/ui/views/controls/textfield/textfield.cc
@@ -558,6 +558,10 @@ const char* Textfield::GetClassName() const {
   return kViewClassName;
 }
 
+gfx::RenderText* Textfield::GetRenderText() {
+  return static_cast<const Textfield*>(this)->GetRenderText();
+}
+
 gfx::NativeCursor Textfield::GetCursor(const ui::MouseEvent& event) {
   bool in_selection = GetRenderText()->IsPointInSelection(event.location());
   bool drag_event = event.type() == ui::ET_MOUSE_DRAGGED;