SpdyStream: Rename and update comments on members.

Part 1 of a larger SpdyStream refactor to HTTP/2 states. This CL streamlines SpdyStream variable names to clarify how they interact with the HTTP/2 state machine (to be added).

R=akalin
BUG=330860

Review URL: https://codereview.chromium.org/149463007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248090 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248090
Start moving context menu code to RenderFrame.

The selection code will have to move as well. That will happen in future changes.

BUG=304341
R=nasko@chromium.org

Review URL: https://codereview.chromium.org/130773004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248091 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248091