Berkshire Hathaway more than tripled the size of its investment in Google's parent company and bought over $2.6 billion worth of Delta Airlines stock as Greg Abel settled into the CEO job after taking over from Warren Buffett at the start of the year. The conglomerate also dumped a number of other stocks, including Visa, Mastercard, Domino's Pizza, Amazon and United Healthcare after the departure late last year of Todd Combs, who was one of the two investment mangers Buffett hired to help manage the portfolio. Buffett was always reluctant to invest in tech companies because he said he didn't understand them well enough to predict the long-term winners. Buffett did make an exception to that rule near the end of his career by buying a massive Apple stake after he recognized how devoted consumers are to that company's iPhones and computers. Abel appears to be more comfortable because by the end of March Berkshire owned nearly 58 million Alphabet shares worth almost $17 billion.…