We now disconnect ourselves if we don't get the server's response to a
keepalive request within 30s. This way we will eventually disconnect if
the network goes away but the socket is not closed.*
* See code.google.com/p/chromium/issues/detail?id=197841 and
https://stackoverflow.com/questions/11755605/chrome-websocket-connection-not-closed-when-browser-closed
We will then try to reconnect once a minute (See 8a10c96);
Keepalives belong at this level anyway, since the format is defined by
both the websocket resource protocol and our specific server url
structure.
// FREEBIE
Update protobuf definitions and refactor message receive and decrypt
codepath to support new protocol, including various flavors of sync
messages (sent messages, contacts, and groups).
Also cleans up background.js and lets libtextsecure internalize
textsecure.processDecrypted and ensure that it is called before handing
DataMessages off to the application.
The Envelope structure now has a generic content field and a
legacyMessage field for backwards compatibility. We'll send outgoing
messages as legacy messages, and sync messages as "content" while
continuing to support both legacy and non-legacy messages on the receive
side until old clients have a chance to transition.
