Move unnecessarily public methods from frames.h into .cc file.
Remove dead StackFrame::SetCallerFp().

R=mstarzinger@chromium.org

Bug: 
Change-Id: I7b66a430cfb01bb38046c9e92f504134ba8316a3
Reviewed-on: https://chromium-review.googlesource.com/602271Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47181}