By Dan Levine SAN FRANCISCO (Reuters) – Four major tech companies including Apple and Google have agreed to settle a lawsuit accusing them of conspiring to hold down salaries in Silicon Valley, just weeks before a high profile trial had been scheduled to begin. The settlement was disclosed in a court filing on Thursday, which did not spell out terms. The case has been closely watched due to the potentially high damages award and a steady disclosure of emails in which Apples late co-founder Steve Jobs, former Google CEO Eric Schmidt and some of their Silicon Valley rivals hatched plans to avoid poaching each others prized engineers. Tech workers filed a class action lawsuit against Apple Inc, Google Inc, Intel Inc and Adobe Systems Inc in 2011, alleging they conspired to refrain from soliciting one anothers employees in order to avert a salary war.