Reland "[KeyedLoadIC] Support Smi "handlers" for element loads"

src/field-index.h

Index: src/field-index.h
diff --git a/src/field-index.h b/src/field-index.h
index 13bb94be41af151ae30f887189b882cbbbd768a7..404c0f613f7ce8367feaf9ba960c4d97aac8a937 100644
--- a/src/field-index.h
+++ b/src/field-index.h
@@ -81,13 +81,6 @@ class FieldIndex final {
   }
   bool operator!=(FieldIndex const& other) const { return !(*this == other); }
 
-  // For GetLoadByFieldOffset.
-  class FieldOffsetIsInobject : public BitField<bool, 1, 1> {};
-  class FieldOffsetIsDouble : public BitField<bool, 2, 1> {};
-  class FieldOffsetOffset : public BitField<int, 3, 27> {};
-  // Make sure we don't overflow into the sign bit.
-  STATIC_ASSERT(FieldOffsetOffset::kNext <= kSmiValueSize - 1);
-
  private:
   FieldIndex(bool is_inobject, int local_index, bool is_double,
              int inobject_properties, int first_inobject_property_offset,