Make PackageOrException.get() public + make loadPackages() variant.

RELNOTES: None
PiperOrigin-RevId: 156876531
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/packages/AbstractPackageLoader.java b/src/main/java/com/google/devtools/build/lib/skyframe/packages/AbstractPackageLoader.java
index ae0343c..953c828 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/packages/AbstractPackageLoader.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/packages/AbstractPackageLoader.java
@@ -250,7 +250,7 @@
 
   @Override
   public ImmutableMap<PackageIdentifier, PackageLoader.PackageOrException> loadPackages(
-      Iterable<PackageIdentifier> pkgIds) throws InterruptedException {
+      Iterable<? extends PackageIdentifier> pkgIds) throws InterruptedException {
     ImmutableList.Builder<SkyKey> keysBuilder = ImmutableList.builder();
     for (PackageIdentifier pkgId : pkgIds) {
       keysBuilder.add(PackageValue.key(pkgId));
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/packages/PackageLoader.java b/src/main/java/com/google/devtools/build/lib/skyframe/packages/PackageLoader.java
index f5b67b1..68b4b0c 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/packages/PackageLoader.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/packages/PackageLoader.java
@@ -40,7 +40,7 @@
    * Package#containsErrors}), e.g. if there was syntax error in the package's BUILD file.
    */
   ImmutableMap<PackageIdentifier, PackageOrException> loadPackages(
-      Iterable<PackageIdentifier> pkgIds) throws InterruptedException;
+      Iterable<? extends PackageIdentifier> pkgIds) throws InterruptedException;
 
   class PackageOrException {
     private final Package pkg;
@@ -56,7 +56,7 @@
      * @throws NoSuchPackageException if there was a non-recoverable error loading the package, e.g.
      *     an io error reading the BUILD file.
      */
-    Package get() throws NoSuchPackageException {
+    public Package get() throws NoSuchPackageException {
       if (pkg != null) {
         return pkg;
       }