According to an article by the Orange County Register, the Chargers have secured a site for temporary team headquarters in Santa Ana if they leave San Diego. But that's not the most important part of the story.
In reality, I think that yesterday's news regarding a new team facility in Santa Ana is a bit of a non-story.
As part of their bid for relocation to Los Angeles, the Chargers have been exploring various sites for months. However, this article in the OC Register reveals a few very important pieces of information about any potential negotiations between the Chargers and San Diego, if they happen.