Adding dep files and dependencies.

vendor/github.com/mesos/mesos-go/api/v0/messenger/sessionid/sessionid.go

@@ -0,0 +1,18 @@
+package sessionid
+
+import (
+	"golang.org/x/net/context"
+)
+
+type key int
+
+const sessionIDKey = 0
+
+func NewContext(ctx context.Context, sessionID string) context.Context {
+	return context.WithValue(ctx, sessionIDKey, sessionID)
+}
+
+func FromContext(ctx context.Context) (string, bool) {
+	sessionID, ok := ctx.Value(sessionIDKey).(string)
+	return sessionID, ok
+}