Refactor HttpBasicStream to store data in HttpBasicState
In preparation for WebSocketBasicHandshakeStream, factor out common member
variables and functionality to a new HttpBasicState class.
See design doc at
https://docs.google.com/a/google.com/document/d/1AH2lRR2i2Wf4yODgckgdsvZeuGwpbvsvMGLnAMUXUbM/edit
and the WebSocketBasicHandshakeStream implementation CL at
https://codereview.chromium.org/
25417005/
BUG=303568
TEST=net_unittests --gtest_filter=HttpBasicState*
Review URL: https://codereview.chromium.org/
44253002
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@231255 0039d316-1c4b-4281-b951-d872f2087c98