What's the gradle equivalent of having another project in your Java build path in Eclipse?

I have an Eclipse workspace that looks like this:

workspace/  
  ProjectA/  
    src/  
  ProjectThatDependsOnA/   
    src/  

In Eclipse, I can go into the Project Properties and edit the java build path of ProjectThatDependsOnA to include "ProjectA". What should I put in my build.gradle in ProjectThatDependsOnA to replicate this behavior in Gradle?