Google Docs code includes references to a new application code-named Brix. The files created using this application are called "Brix documents", so Brix can't be a photo editor or a video editor.
Here's an icon that could be used for Brix documents: it shows some Lego bricks. "Lego consists of colorful interlocking plastic bricks and an accompanying array of gears, minifigures and various other parts. Lego bricks can be assembled and connected in many ways, to construct such objects as vehicles, buildings, and even working robots," informs Wikipedia. Maybe Brix is just a collaborative web application based on SketchUp.
There are also icons for Fusion Table documents and Google Sites, which could be included in Google Docs: