Remove default constructors for QuicTime and QuicTime::Delta and used static Zero() methods instead…

Remove default constructors for QuicTime and QuicTime::Delta and used static Zero() methods instead to make it clear what value is being used.  One annoying side-effect is this means that maps which have these objects as keys can't not be accessed with [].  Thankfully, this is not a huge problem.  (It only affects us in one place).  But I can add the default constructors back to support this use case, if necessary.  (I'd prefer not to since I think Zero() is more clear, but can go either way).

Merge internal change: 40993340

[jar (doing other things), 2013-01-17 01:50:33]

lgtm

https://codereview.chromium.org/11961022/diff/1/net/quic/quic_time.cc
File net/quic/quic_time.cc (right):

https://codereview.chromium.org/11961022/diff/1/net/quic/quic_time.cc#newcode14
net/quic/quic_time.cc:14: QuicTime::Delta::Delta(base::TimeDelta delta_)
nit: use an arg name without the trailing underscore.

[Ryan Hamilton, 2013-01-17 18:44:18]

https://codereview.chromium.org/11961022/diff/1/net/quic/quic_time.cc
File net/quic/quic_time.cc (right):

https://codereview.chromium.org/11961022/diff/1/net/quic/quic_time.cc#newcode14
net/quic/quic_time.cc:14: QuicTime::Delta::Delta(base::TimeDelta delta_)
On 2013/01/17 01:50:33, jar wrote:
> nit: use an arg name without the trailing underscore.

Done.