Rename closing_* in WebSocketChannel to received_close_* and do some refactoring
- Variable renaming: they should be prefixed with received_ so that
reviewer can understand that they store values received from the
server
- HandleFrame() is just a part of ProcessFrame(). I want them to have
names from which we can see that
- Factor out the switch-clause in HandleFrame building a frame type
string as the method is very long
BUG=none
Review URL: https://codereview.chromium.org/
131333010
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250983 0039d316-1c4b-4281-b951-d872f2087c98