By Yuvraj Malik and Dawn Chmielewski (Reuters) -Rupert Murdoch has started a process that could reunite his media empire, News Corp and Fox Corp disclosed on Friday, saying they would consider combining at his behest, nearly a decade after the companies split. Both have formed special committees to review proposals of a potential combination, they said. If a deal goes through, the combination will allow Murdoch greater control over his media assets and help the companies trim costs. Media companies are fighting decades-low growth in advertising sales and for users’ attention against deep-pocke…