<p>If you remove from our services any content that’s covered by this license, then our systems will stop making that content publicly available in a reasonable amount of time. There are two exceptions:</p> <ul> <li>If you already shared your content with others before removing it. For example, if you shared a photo with a friend who then made a copy of it, or shared it again, then that photo may continue to appear in your friend’s Google Account even after you remove it from your Google Account.</li> <li>If you make your content available through other companies’ services, it’s possible that search engines, including Google Search, will continue to find and display your content as part of their search results.

Given the exceptions specified, plus the gigantic scope of the Google Search engine, there's plenty of reason to argue that content is, technically speaking, kept by them even after deletion.