Simplify lifetime management of ValidateClientHelloResultCallback::Result objects

Simplify lifetime management of ValidateClientHelloResultCallback::Result objects

The lifetimes of ValidateClientHelloResultCallback::Result objects are
managed by bare new/delete.  These objects are also passed around by
pointer which gives no indication as to who is managing the lifetime,
and many methods are passed both a pointer to a Result object as w
ell as a reference to a sub-object.  This CL eliminates these patterns.

Migrating from bare pointers to unique_ptr in some quic codepaths.  No
functional change intended, not flag-protected.

Merge internal change: 132359769

[Ryan Hamilton, 2016-09-13 20:30:44]

rch@chromium.org changed reviewers:
+ zhongyi@chromium.org

[Zhongyi Shi, 2016-09-13 21:18:44]

lgtm