Implement getNamespace() for deserialized scope

DescriptorFinder now can find packages, pull the method up from
AbstractDescriptorFinder class

compiler/frontend/serialization/src/org/jetbrains/jet/descriptors/serialization/AbstractDescriptorFinder.java

@@ -23,10 +23,8 @@ import org.jetbrains.jet.descriptors.serialization.descriptors.AnnotationDeseria
 import org.jetbrains.jet.descriptors.serialization.descriptors.DeserializedClassDescriptor;
 import org.jetbrains.jet.lang.descriptors.ClassDescriptor;
 import org.jetbrains.jet.lang.descriptors.DeclarationDescriptor;
-import org.jetbrains.jet.lang.descriptors.NamespaceDescriptor;
 import org.jetbrains.jet.lang.resolve.lazy.storage.MemoizedFunctionToNullable;
 import org.jetbrains.jet.lang.resolve.lazy.storage.StorageManager;
-import org.jetbrains.jet.lang.resolve.name.FqName;
 
 import static org.jetbrains.jet.lang.resolve.lazy.storage.StorageManager.ReferenceKind.STRONG;
 
@@ -52,7 +50,7 @@ public abstract class AbstractDescriptorFinder implements DescriptorFinder {
                 ProtoBuf.Class classProto = classData.getClassProto();
 
                 DeclarationDescriptor owner =
-                        classId.isTopLevelClass() ? getPackage(classId.getPackageFqName()) : findClass(classId.getOuterClassId());
+                        classId.isTopLevelClass() ? findPackage(classId.getPackageFqName()) : findClass(classId.getOuterClassId());
                 assert owner != null : "No owner found for " + classId;
 
                 AbstractDescriptorFinder _this = AbstractDescriptorFinder.this;
@@ -74,8 +72,5 @@ public abstract class AbstractDescriptorFinder implements DescriptorFinder {
     @Nullable
     protected abstract ClassData getClassData(@NotNull ClassId classId);
 
-    @NotNull
-    protected abstract NamespaceDescriptor getPackage(@NotNull FqName fqName);
-
     protected abstract void classDescriptorCreated(@NotNull ClassDescriptor classDescriptor);
 }

compiler/frontend/serialization/src/org/jetbrains/jet/descriptors/serialization/DescriptorFinder.java

@@ -19,17 +19,27 @@ package org.jetbrains.jet.descriptors.serialization;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.descriptors.ClassDescriptor;
+import org.jetbrains.jet.lang.descriptors.NamespaceDescriptor;
+import org.jetbrains.jet.lang.resolve.name.FqName;
 
 public interface DescriptorFinder {
-
     DescriptorFinder EMPTY = new DescriptorFinder() {
         @Nullable
         @Override
         public ClassDescriptor findClass(@NotNull ClassId classId) {
             return null;
         }
+
+        @Nullable
+        @Override
+        public NamespaceDescriptor findPackage(@NotNull FqName name) {
+            return null;
+        }
     };
 
     @Nullable
     ClassDescriptor findClass(@NotNull ClassId classId);
+
+    @Nullable
+    NamespaceDescriptor findPackage(@NotNull FqName name);
 }

compiler/frontend/serialization/src/org/jetbrains/jet/descriptors/serialization/descriptors/DeserializedPackageMemberScope.java

@@ -116,4 +116,10 @@ public abstract class DeserializedPackageMemberScope extends DeserializedMemberS
     protected void addNonDeclaredDescriptors(@NotNull Collection<DeclarationDescriptor> result) {
         // Do nothing
     }
+
+    @Nullable
+    @Override
+    public NamespaceDescriptor getNamespace(@NotNull Name name) {
+        return descriptorFinder.findPackage(packageFqName.child(name));
+    }
 }