Encapsulate record operations

This change is a pure refactor that puts operations on a record object
as a member method. Also add some javadocs.

Bug: b/360129098
Test: atest CtsMediaBetterTogetherTestCases CtsMediaHostTestCases
Flag: EXEMPT refactor
Change-Id: Ie703b3bfebb42430a91d7e6701518d613e00b1e9