making a gviz chart with angular js

I'm trying to make this gviz pie chart from the example here example https://google-developers.appspot.com/chart/interactive/docs/quick_start in angularjs.

What services do I need to write?

The example code above uses

1. A google ajax library to load the gviz library
2. A gviz dataTable.
3. A gviz pie chart
4. document.getElementById

It seems like I'll need to write my own service for each of these, except $document. Is this true? That seems like an awful lot of boiler plate =/ (Side question, why is wrapping these as a service a good thing?)

Can someone take a stab at what the dataTable service might look like? I'm really not sure how to get access to google.visualization.DataTable() to 'translate' this line.

var data = new google.visualization.DataTable();