Remove a scoped_refptr<>::swap overload

A scoped_refptr<>::swap overload is used to insert or remove the internal
pointer without manipulating the ref count. That functionality should not
be exposed, or at least, should be exposed separately with better name.

This CL removes the swap() overload, and rewrites callers without swap().

Review-Url: https://codereview.chromium.org/2723083004
Cr-Commit-Position: refs/heads/master@{#455407}
3 files changed