Refactoring: Hide or remove some methods of Resource

This CL hides or removes some methods of Resource for code health.

There was only one usage of resourceTypeName, which was removed at
crrev.com/1889973002.

BUG=n/a

Review-Url: https://codereview.chromium.org/2164553002
Cr-Commit-Position: refs/heads/master@{#406513}
3 files changed