The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6dfc89d2b46fc83f3ee942c246a6c248ff151f2f

commit 6dfc89d2b46fc83f3ee942c246a6c248ff151f2f
Author: Marina Ciocea <marinaciocea@chromium.org>
Date: Mon May 21 08:41:27 2018

Add memory metrics for audio service utility process.

This CL adds Memory.AudioService.PrivateMemoryFootprint, SharedMemoryFootprint and
PrivateSwapFootprint metrics, and content::GetProcessIdForAudioService() to read audio
service process id.

Audio service design doc: https://docs.google.com/document/d/1s_Fd1WRDdpb5n6C2MSJjeC3fis6hULZwfKMeDd4K5tI/edit?usp=sharing

Bug:  843985 
Change-Id: I8d8c9cd77c8dcd3a6ec836a8f74f36617a9e7f67
Reviewed-on: https://chromium-review.googlesource.com/1064064
Commit-Queue: Marina Ciocea <marinaciocea@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Erik Chen <erikchen@chromium.org>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560248}
[modify] https://crrev.com/6dfc89d2b46fc83f3ee942c246a6c248ff151f2f/chrome/browser/metrics/process_memory_metrics_emitter.cc
[modify] https://crrev.com/6dfc89d2b46fc83f3ee942c246a6c248ff151f2f/chrome/browser/metrics/process_memory_metrics_emitter_unittest.cc
[modify] https://crrev.com/6dfc89d2b46fc83f3ee942c246a6c248ff151f2f/content/public/browser/BUILD.gn
[add] https://crrev.com/6dfc89d2b46fc83f3ee942c246a6c248ff151f2f/content/public/browser/audio_service_info.cc
[add] https://crrev.com/6dfc89d2b46fc83f3ee942c246a6c248ff151f2f/content/public/browser/audio_service_info.h
[modify] https://crrev.com/6dfc89d2b46fc83f3ee942c246a6c248ff151f2f/tools/metrics/histograms/histograms.xml

[bulk-edit: disregard if N/A] Can the owner please set milestone to this bug if applicable?