Cleanup after the switch of Database::query() to return ResultWrapper
instead of resource.
* Soft-deprecate the IResultWrapper accessors in IDatabase.
* Move relevant DBMS-specific functionality to ResultWrapper subclasses.
The deprecated methods in IResultWrapper become short and simple.
ResultWrapper is now abstract (b/c break).
* Move the implementation of fieldName(), numFields() and one of the
fieldInfo() implementations to the ResultWrapper subclass in order to
avoid ResultWrapper::unwrap() calls.
* Make Database::doQuery() return a ResultWrapper subclass instead of
underlying result data, so that the Database parent class does not
need to be aware of wrapper construction.
* Hard-deprecate ResultWrapper::unwrap(),
DatabaseMysqlBase::fieldType(), DatabasePostgres::fieldType().
* Fix the inefficient seeking method in SQLite.
* Make FakeResultWrapper extend ResultWrapper with an implementation
similar to the SQLite one. This is possible because ResultWrapper does
not depend on IDatabase anymore.
* Resolve fixme in DatabasePostgres: from studying the source,
neither pg_fetch_object() nor pg_num_rows() can set an error
retrievable with pg_last_error(). Removed unnecessary warning
suppression.
* ResultWrapperTest didn't make sense as a unit test anymore, so I
adapted it as an integration test against the current DBMS.
This change also means that ResultWrapper::key() always gives the
correct offset, even if Iterator methods are not being used.
Bug: T286694
Change-Id: I935835316c0bd7d3d061bd8fde9c9ce99ce756ec
bc76602493