Retry updates that have not been acknowledged.

If we do not get a reply from the server acknowledging our update after 5 seconds,
send it again. If it never got to the server, this is like normal. If the update
got to the server, but we never received the ack then we need to rely on ShareJs's
duplicate handling. We set the dupIfSource parameter on any retried updates which
let ShareJs know that it's a dup if we already have an op with this version number
and client id. The doc-updater and real-time services need changes to correctly
send another ack only to the submitting client in the case of a duplicate update.

services/web/public/coffee/ide/editor/Document.coffee

@@ -150,14 +150,10 @@ define [
 				wantToBeJoined: @wantToBeJoined
 				update: update
 
-			if Math.random() < (@ide.disconnectRate or 0)
-				console.log "Simulating disconnect"
-				@ide.connectionManager.disconnect()
-				return
-
-			if Math.random() < (@ide.ignoreRate or 0)
-				console.log "Simulating lost update"
-				return
+			if window.dropAcks? and Math.random() < window.dropAcks
+				if !update.op? # Only drop our own acks, not collaborator updates
+					console.log "Simulating a lost ack", update
+					return
 
 			if update?.doc == @doc_id and @doc?
 				@doc.processUpdateFromServer update

services/web/public/coffee/ide/editor/ShareJsDoc.coffee

@@ -28,8 +28,13 @@ define [
 			@connection = {
 				send: (update) =>
 					@_startInflightOpTimeout(update)
+					if window.dropUpdates? and Math.random() < window.dropAcks
+						console.log "Simulating a lost update", update
+						return
 					@socket.emit "applyOtUpdate", @doc_id, update
 				state: "ok"
+				# Unlike ShareJs, our connection.id never changes, even when we disconnect/reconnect.
+				# This gives this client a unique id used for detecting duplicates ops.
 				id:    @socket.socket.sessionid
 			}
 
@@ -90,7 +95,6 @@ define [
 
 		updateConnectionState: (state) ->
 			@connection.state = state
-			@connection.id = @socket.socket.sessionid
 			@_doc.autoOpen = false
 			@_doc._connectionStateChanged(state)
 
@@ -103,13 +107,18 @@ define [
 		attachToAce: (ace) -> @_doc.attach_ace(ace, false, window.maxDocLength)
 		detachFromAce: () -> @_doc.detach_ace?()
 	
-		INFLIGHT_OP_TIMEOUT: 10000
+		INFLIGHT_OP_TIMEOUT: 5000
 		_startInflightOpTimeout: (update) ->
-			meta =
-				v: update.v
-				op_sent_at: new Date()
 			timer = setTimeout () =>
-				@trigger "op:timeout", update
+				# Only send the update again if inflightOp is still populated
+				# This can be cleared when hard reloading the document in which
+				# case we don't want to keep trying to send it.
+				if @_doc.inflightOp?
+					update.dupIfSource = [@connection.id]
+					@connection.send(update)
+				# TODO: Trigger op:timeout only when some max retries have been hit
+				# and we need to do a full reload.
+				# @trigger "op:timeout", update
 			, @INFLIGHT_OP_TIMEOUT
 			@_doc.inflightCallbacks.push () =>
 				clearTimeout timer