The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d86819e7d7099aa720287ff1abf46a83628e65f3

commit d86819e7d7099aa720287ff1abf46a83628e65f3
Author: Stuart Langley <slangley@chromium.org>
Date: Fri Jun 15 02:20:18 2018

Add UMA metrics for TeamDrive full, delta and directory fetch.

UMAs already existed for full and directory fetch, so just added
a new histogram for TeamDrives.

Added UMA for delta fetch for both the default corpus and a TeamDrive.

Added expiry dates for the three UMAs.

I couldn't find an example of how to test that the correct UMAs are
being written in a C++ test, hence there's no tests.

Bug:  843446 
Change-Id: Ifd000cabc02f1b0e4cd7cf599fe83d9bfa74b8f5
Reviewed-on: https://chromium-review.googlesource.com/1092959
Commit-Queue: Stuart Langley <slangley@chromium.org>
Reviewed-by: Gayane Petrosyan <gayane@chromium.org>
Reviewed-by: Sasha Morrissey <sashab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567519}
[modify] https://crrev.com/d86819e7d7099aa720287ff1abf46a83628e65f3/components/drive/change_list_processor_unittest.cc
[modify] https://crrev.com/d86819e7d7099aa720287ff1abf46a83628e65f3/components/drive/chromeos/change_list_loader.cc
[modify] https://crrev.com/d86819e7d7099aa720287ff1abf46a83628e65f3/components/drive/chromeos/change_list_processor.cc
[modify] https://crrev.com/d86819e7d7099aa720287ff1abf46a83628e65f3/components/drive/chromeos/change_list_processor.h
[modify] https://crrev.com/d86819e7d7099aa720287ff1abf46a83628e65f3/components/drive/chromeos/directory_loader.cc
[modify] https://crrev.com/d86819e7d7099aa720287ff1abf46a83628e65f3/components/drive/file_system_core_util.cc
[modify] https://crrev.com/d86819e7d7099aa720287ff1abf46a83628e65f3/components/drive/file_system_core_util.h
[modify] https://crrev.com/d86819e7d7099aa720287ff1abf46a83628e65f3/tools/metrics/histograms/histograms.xml