Improve linker_verbose_tracking.py

linker_verbose_tracking.py is used to analyze the verbose output from
the VC++ linker to help understand binary-size regressions. However some
of its messages are clear only to the original author, and it completely
fails on the utf-16 files created when redirecting the linker output
from powershell.

This change updates the script to handle both utf-16 and utf-8 files,
and improves the messages printed in a couple of cases.

R=dvallet@chromium.org
BUG=714841

Review-Url: https://codereview.chromium.org/2863843003
Cr-Commit-Position: refs/heads/master@{#469783}
1 file changed