Yes, [it says that](http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml?showone=Names_and_Order_of_Includes#Names_and_Order_of_Includes) it prefers you put them in the header file.  I happen to agree with this.  Bullet point 1:

```bash
In dir/foo.cc or dir/foo_test.cc, whose main purpose is to implement or test the stuff in dir2/foo2.h, order your includes as follows:

1. dir2/foo2.h (preferred location — see details below).
2. C system files.
3. C++ system files.
4. Other libraries' .h files.
5. Your project's .h files.
```