diagnose_bloat.py: update logging and general clean up.

diagnose_bloat.py: update logging and general clean up.

Changed the script to use the logging module where possible and added a
--silent flag that hides gclient/ninja output. Also added stderr to
Ninja output so that users can check why a build failed.

Changed the branch restore function to use atexit so that the original
branch will be restored if ctrl-c is pressed while another rev is
checked out.

BUG=695182
Review-Url: https://codereview.chromium.org/2857073002
Cr-Commit-Position: refs/heads/master@{#469043}
Committed: https://chromium.googlesource.com/chromium/src/+/40a227b78d6fed53d06420553275557179546502

[estevenson, 2017-05-03 17:44:17]

estevenson@chromium.org changed reviewers:
+ agrieve@chromium.org

[estevenson, 2017-05-03 17:44:18]

ptal!

[agrieve, 2017-05-03 18:11:06]

On 2017/05/03 17:44:18, estevenson wrote:
> ptal!

lgtm

[estevenson, 2017-05-03 18:21:58]

The CQ bit was checked by estevenson@chromium.org

[commit-bot: I haz the power, 2017-05-03 18:22:32]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-03 18:38:40]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1493835718163230,
"parent_rev": "73af8befbc973943ac062ccd7d48b73ecc61de60", "commit_rev":
"40a227b78d6fed53d06420553275557179546502"}

[commit-bot: I haz the power, 2017-05-03 18:39:42]

Description was changed from

==========
diagnose_bloat.py: update logging and general clean up.

Changed the script to use the logging module where possible and added a
--silent flag that hides gclient/ninja output. Also added stderr to
Ninja output so that users can check why a build failed.

Changed the branch restore function to use atexit so that the original
branch will be restored if ctrl-c is pressed while another rev is
checked out.

BUG=695182
==========

to

==========
diagnose_bloat.py: update logging and general clean up.

Changed the script to use the logging module where possible and added a
--silent flag that hides gclient/ninja output. Also added stderr to
Ninja output so that users can check why a build failed.

Changed the branch restore function to use atexit so that the original
branch will be restored if ctrl-c is pressed while another rev is
checked out.

BUG=695182

Review-Url: https://codereview.chromium.org/2857073002
Cr-Commit-Position: refs/heads/master@{#469043}
Committed:
https://chromium.googlesource.com/chromium/src/+/40a227b78d6fed53d06420553275...
==========

[commit-bot: I haz the power, 2017-05-03 18:39:43]

Committed patchset #3 (id:40001) as
https://chromium.googlesource.com/chromium/src/+/40a227b78d6fed53d06420553275...