Unify usage of logging/assert macros in base/

* Enables following checks in Release+DCHECK_ALWAYS_ON build (previous DCHECKs behind !NDEBUG):
 - icu_util
 - LazyInstance
 - CancellationFlag

* Unifies ENABLE_DLOG into DCHECK_IS_ON()

* Mass replaces (!NDEBUG || DCHECK_ALWAYS_ON) with DCHECK_IS_ON()

TBR=rkaplow, alokp, boliu
 - rkaplow for chrome/browser/metrics/ side-effects
 - alokp for chromecast/ side-effects
 - boliu for device/power_save_blocker/ side-effects
BUG=622400
(grew tired of DCHECKs behind NDEBUG when writing
https://codereview.chromium.org/2135413003/ for https://codereview.chromium.org/2103883004/#msg14)

Review-Url: https://codereview.chromium.org/2163023002
Cr-Commit-Position: refs/heads/master@{#409036}
21 files changed