Google is set to unveil its new Chromecast 4K and digital assistant Google Home at an event next week, but while Amazon will be wary of Google encroaching on its smart home hub territory, both companies should be more concerned about Roku’s move to sweep the market with a suite of new devices. The 4K Chromecast will retail at $69 and inside sources have claimed it will be adding HDR to the mix. Groans of disappointment will echo around the streaming device market if it fails to include HDR, particularly as Roku’s newest HDR devices range from $100 to $129. This puts Roku in an unfamiliar position – shifting from undercutting Chromecast and Fire TV Stick devices, to barging fearlessly…