Introduce SkylarkRepositoryModule

The SkylarkRepositoryModule declare the `repository_rule` function
to Skylark to define new remote repository types (http://goo.gl/OZV3o0).
The work is delagated to the `SkylarkRepositoryFunction` by the
`RepositoryDelegatorFunction`. `SkylarkRepositoryContext` defines the
`ctx` object passed to the `repository_rule` implementation function.

This change also introduce a `SkylarkPath` and the necessary methods
in `SkylarkRepositoryContext` to showcase the creation of a
`local_repository` like repository.

Issue #893: step 3 of the roadmap http://goo.gl/OZV3o0.

--
MOS_MIGRATED_REVID=114895003

1 files changed, 7 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/packages/PackageFactory.java b/src/main/java/com/google/devtools/build/lib/packages/PackageFactory.java
index 055ef73bf9..36213d53fe 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/PackageFactory.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/PackageFactory.java
@@ -1398,6 +1398,13 @@ public final class PackageFactory {
     public MakeEnvironment.Builder getMakeEnvironment() {
       return pkgBuilder.getMakeEnvironment();
     }
+
+    /**
+     * Returns the builder of this Package.
+     */
+    public Package.Builder getBuilder() {
+      return pkgBuilder;
+    }
   }
 
   private final ClassObject nativeModule;