Port 531dde9f

Original commit message:
    The new step-in implementation no longer tries to predict the step-in
    target, so we don't need the arguments count nor call type anymore.

R=yangguo@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1490413002

Cr-Commit-Position: refs/heads/master@{#32533}