GitLab

Adding:
* Signin.SSOIdentityListRequest.FetchIdentitiesWithCallback.Duration
  Time needed to fetch the identity list

* Signin.SSOIdentityListRequest.RunAfterCacheIsPopulated.CacheState
  State of the identity cache before calling RunAfterCacheIsPopulated()

* Signin.SSOIdentityListRequest.RunAfterCacheIsPopulated.Duration
  Time needed for the callback to be called for
  RunAfterCacheIsPopulated()

* Signin.SSOIdentityListRequest.WaitUntilCacheIsPopulated.CacheState
  State of the identity cache before calling RunAfterCacheIsPopulated()

* Signin.SSOIdentityListRequest.WaitUntilCacheIsPopulated.Duration
  Time blocked in WaitUntilCacheIsPopulated()

Those metrics are implemented in crrev.com/i/3353162.

Design doc:
http://go/async-identityservice-api

   crrev.com/c/2489915 Adding methods in ChromeIdentityService
   crrev.com/i/3353161 Implementing in ChromeIdentityServiceImpl
=> crrev.com/c/2490110 Adding metrics
   crrev.com/i/3353162 Implementing the metrics
   crrev.com/c/2490010 Adding WaitUntilCacheIsPopulated calls
   crrev.com/i/3354983 Adding DCHECK for cache state

Bug: 897470
Change-Id: I83744b7eaec3f7eb4c2515550e6a2638e5c0ec15
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2490110
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824387}