At 4:53 of the second period in the Flames/Blackhawks game, Calgary requested a Coach's Challenge to review whether Ryan Hartman interfered with Flames goaltender Mike Smith prior to his goal.
After reviewing all available replays and consulting with NHL Hockey Operations staff, the Referee determined that Hartman prevented Smith from doing his job in his crease, in accordance with Rule 78.7 which states in part: "The standard for overturning the call in the event of a 'GOAL' call on the ice is that the Referee ... determines that the goal should have been disallowed due to 'Interference on the Goalkeeper,' as described in Rules 69.1, 69.3 and 69.4."
Rule 69.1 states that goals should be disallowed if "an attacking player, either by his positioning or by contact, impairs the goalkeeper's ability to move freely within his crease or defend his goal."
Therefore the original call is overturned - no goal Chicago Blackhawks.
Since the Coach's Challenge resulted in the original call being overturned, the Calgary Flames retain their time-out.