Move non-trivial methods from QuicDataWriter to the .cc file.

Remove the unused AdvancePointer method.

Merge internal change 35490203


Review URL: https://chromiumcodereview.appspot.com/11230005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@163185 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed