Remove most code related to serialized properties

Nearly completely implemented in terms of custom properties.
`_before_type_cast` now stores the raw serialized string consistently,
which removes the need to keep track of "state". The following is now
consistently true:

- `model.serialized == model.reload.serialized`
- A model can be dumped and loaded infinitely without changing
- A model can be saved and reloaded infinitely without changing

1 files changed, 2 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/column.rb b/activerecord/lib/active_record/connection_adapters/column.rb
index 4fbc55a07e..60da541e3d 100644
--- a/activerecord/lib/active_record/connection_adapters/column.rb
+++ b/activerecord/lib/active_record/connection_adapters/column.rb
@@ -17,7 +17,7 @@ module ActiveRecord
 
       delegate :type, :precision, :scale, :limit, :klass, :accessor,
         :text?, :number?, :binary?, :serialized?,
-        :type_cast, :type_cast_for_write, :raw_type_cast_for_write, :type_cast_for_database,
+        :type_cast, :type_cast_for_write, :type_cast_for_database,
         :type_cast_for_schema,
         to: :cast_type
 
@@ -52,7 +52,7 @@ module ActiveRecord
       end
 
       def extract_default(default)
-        type_cast(default)
+        type_cast_for_write(type_cast(default))
       end
     end
   end