sync: Refactor MutablEntry internals

This is a follow-up to r223111.  That change modified the public
interface of MutableEntry to expose one setter function for each mutable
field in the EntryKernel.

This change modifies the internals of MutableEntry to match the external
API.  Many of the shared setter functions used to diverge significantly
based on which field was being set.  Now that each field has its own
setter, it's easier to provide different setter implementations for each
field.

Some of these changes might make it look like we're unnecessarily
introducing copy+paste code.  However, we have more CLs on the way that
introduce more differences among the setters.  In particular, many of
the SERVER_* field setters will be modified to no longer call
SaveOriginal().

BUG=284672

Review URL: https://chromiumcodereview.appspot.com/23435008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@223537 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed