Land Recent QUIC changes.

Move the QuicPacketWriter to the QuicConnection from the Helper. Also
changes the TestWriters to wrap another writer, instead of
re-implementing the default writer logic.

Merge internal change: 53858038

Adding an end to end test to simulate the socket being write blocked 10%
of the time.

Merge internal change: 53813433

R=rch@chromium.org

Review URL: https://codereview.chromium.org/37733002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230566 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 230566
Blink roll 160353:160385

http://build.chromium.org/f/chromium/perf/dashboard/ui/changelog_blink.html?url=/trunk&range=160354:160385&mode=html
TBR=
BUG=

Review URL: https://codereview.chromium.org/37773004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230567 0039d316-1c4b-4281-b951-d872f2087c98
Update .DEPS.git

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230568 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 230567
SVN changes up to revision 230568