There has been ongoing talk about Google merging Android and Chrome. Despite seeing some crossover such as the touchscreen display being added to the Chromebook Pixel, or peripheral support being improved back in Honeycomb -- Google is not pushing to merge the platforms anytime soon. In fact, Matias Duarte recently spoke with SlashGear and said that the "two platforms meet different needs.”
That is not to say that a merge could not happen at some point in the future though. Duarte noted that Android and Chrome will remain independent platforms as long as it makes functional sense. One interesting aspect, it seems that despite Android being the bigger of the two platforms, Chrome (the team) has been an influence. Duarte mentioned that "Chrome on Android is the best browser we’ve ever had, and we would not be at that level without the Chrome team doing the work that they do."
Maybe this will have some reverse crossover in that Android will help to improve the touchscreen functionality in Chrome OS. More specifically at the moment, on the Chromebook Pixel. In fact, it seems Duarte believes that all devices should be touchscreen. He noted that he thinks "every screen should be a touchscreen in the future, regardless if it has a keyboard or not.”
It seems that at some point the two platforms would converge. Whether that means Chrome OS merging into Android or the opposite. Of course, given the current dominance of Android, we suspect that if this ever happens -- it will be Chrome coming to Android. Speculation aside, at the moment we have two platforms coming from Google and judging from the comments from Duarte, it looks like that is how it will remain for the foreseeable future.