Consolidate calls to clock sources to OfflineClock #2

This change further changes direct calls to Time::Now or the default
base::Clock instance to an OfflineClock module within classes which
need a Clock pointer to be passed into the class. This eliminates the
need for testing-only functions and further allows ease of testing.

chrome/browser/offline_pages

Bug: 906903
Change-Id: I99d5c7e518465035ff8317f17be68ed776603f8d
Reviewed-on: https://chromium-review.googlesource.com/c/1357551
Commit-Queue: Mark Lieu <mtlieuu@chromium.org>
Reviewed-by: Carlos Knippschild <carlosk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614473}
9 files changed