An interesting attack and something that we'll consider. HTTP/2 should add a significant amount of noise to this, but ultimately adding random padding to every response or padding that compresses to a consistent length would be the best solution.
The important thing to hide on news sites is not so much what you're reading (who cares, it's public news and clicking through a link means nothing), but rather hiding your username for the comments section.
"I'm all in favor of news sites using HTTPS, but I assume they're also going to pad all their articles to a uniform length?" -- https://twitter.com/matthew_d_green/status/53504312624809574...