The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a1ee205ef9f3dce6af516cf18a7b6426ebbd8d55

commit a1ee205ef9f3dce6af516cf18a7b6426ebbd8d55
Author: rkaplow <rkaplow@chromium.org>
Date: Tue Sep 27 17:12:08 2016

Refactor histogram_macros.h.

This improves documentation for the macros in the file, moves LOCAL_* to a seperate file, and hides the internal macros that do not need to be exposed to histogram users into an internal file. This doesn't require any client changes as both files are includes in histogram_macros.h

BUG= 649410 

Review-Url: https://codereview.chromium.org/2361933002
Cr-Commit-Position: refs/heads/master@{#421241}

[modify] https://crrev.com/a1ee205ef9f3dce6af516cf18a7b6426ebbd8d55/base/metrics/histogram_base.h
[modify] https://crrev.com/a1ee205ef9f3dce6af516cf18a7b6426ebbd8d55/base/metrics/histogram_macros.h
[add] https://crrev.com/a1ee205ef9f3dce6af516cf18a7b6426ebbd8d55/base/metrics/histogram_macros_internal.h
[add] https://crrev.com/a1ee205ef9f3dce6af516cf18a7b6426ebbd8d55/base/metrics/histogram_macros_local.h
[modify] https://crrev.com/a1ee205ef9f3dce6af516cf18a7b6426ebbd8d55/base/metrics/histogram_snapshot_manager.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/7c83caef73ee8be2d2068c3aff34a11e6d515c44

commit 7c83caef73ee8be2d2068c3aff34a11e6d515c44
Author: rkaplow <rkaplow@chromium.org>
Date: Tue Oct 04 22:37:55 2016

Add a basic exact linear macro. Ends up being the same as enum, but making it explicit will make our API more understandable, as a user shouldn't need to know the detail that enum is actually just 0-1, 1-2, etc.

Also adding mpearson@ and I as owners
BUG= 649410 

Review-Url: https://codereview.chromium.org/2385053003
Cr-Commit-Position: refs/heads/master@{#422971}

[modify] https://crrev.com/7c83caef73ee8be2d2068c3aff34a11e6d515c44/base/metrics/OWNERS
[modify] https://crrev.com/7c83caef73ee8be2d2068c3aff34a11e6d515c44/base/metrics/histogram_macros.h