Access-time threshold unit failure in CookieMonster.

net/cookies/cookie_monster.h

Index: net/cookies/cookie_monster.h
diff --git a/net/cookies/cookie_monster.h b/net/cookies/cookie_monster.h
index a88f166b43d90971f436a56d22261e9cb6b3f0e5..599f708b2199478ec1b4bd29dd1f557e449f16f5 100644
--- a/net/cookies/cookie_monster.h
+++ b/net/cookies/cookie_monster.h
@@ -140,7 +140,7 @@ class NET_EXPORT CookieMonster : public CookieStore {
   // Only used during unit testing.
   CookieMonster(PersistentCookieStore* store,
                 CookieMonsterDelegate* delegate,
-                int last_access_threshold_milliseconds);
+                const base::TimeDelta& last_access_threshold);

[Ryan Hamilton, 2016/05/18 22:45:20]

nit: base::TimeDelta is (under the covers) an int64_t. As such, passing by value
instead of by const-ref seems better.  

[Ryan Sleevi, 2016/05/18 23:07:07]

The fact that it had to be clarified "(under the covers)" gives a hint about why
I might disagree. In any event, either approach is consistent with this file,
which is itself inconsistent (although the const-ref is far, far more consistent
in the wider codebase)

[Scott Hess - ex-Googler, 2016/05/18 23:14:29]

Done.

[Scott Hess - ex-Googler, 2016/05/18 23:14:29]

My of const& was _mostly_ because I assumed that the class was forward-declared,
and thus you wouldn't be able to pass by value.  I'll leave if const-value.

[Ryan Hamilton, 2016/05/18 23:46:16]

Hm. I'm surprised to hear you say this, because in the past you proposed using a
vector<string> and doing a binary search instead of (what?) a hash_set<string>
because of short string optimization (which requires knowledge of the under-the
hood representation of string). How would you characterize the difference
between these two situations? There's probably a guiding principle here that
I've not thought about.

That being said, +1 for consistency. I only looked at this CL 'cause shess G+'d
about it and the const& just caught my eye, but I didn't actually look at the
surrounding code :>

 
   ~CookieMonster() override;