DescriptorFinder now can find class names in a package

This helps to get rid of "repeated class_name" field in Package protobuf
message. DescriptorFinder in resolve.java uses PSI to find all classes in a
package, and the finder for built-ins just reads .kotlin_class_names file

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/DeserializedDescriptorResolver.java

@@ -35,6 +35,7 @@ import org.jetbrains.jet.lang.resolve.java.AbiVersionUtil;
 import org.jetbrains.jet.lang.resolve.java.JvmStdlibNames;
 import org.jetbrains.jet.lang.resolve.lazy.storage.LockBasedStorageManager;
 import org.jetbrains.jet.lang.resolve.name.FqName;
+import org.jetbrains.jet.lang.resolve.name.Name;
 import org.jetbrains.jet.lang.resolve.scopes.JetScope;
 import org.jetbrains.jet.utils.ExceptionUtils;
 
@@ -42,6 +43,7 @@ import javax.inject.Inject;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 
 import static org.jetbrains.asm4.ClassReader.*;
@@ -75,6 +77,12 @@ public final class DeserializedDescriptorResolver {
         public NamespaceDescriptor findPackage(@NotNull FqName name) {
             return javaNamespaceResolver.resolveNamespace(name);
         }
+
+        @NotNull
+        @Override
+        public Collection<Name> getClassNames(@NotNull FqName packageName) {
+            return javaNamespaceResolver.getClassNamesInPackage(packageName);
+        }
     };
 
     @Inject

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/JavaNamespaceResolver.java

@@ -39,12 +39,11 @@ import org.jetbrains.jet.lang.resolve.java.scope.JavaClassStaticMembersScope;
 import org.jetbrains.jet.lang.resolve.java.scope.JavaPackageScopeWithoutMembers;
 import org.jetbrains.jet.lang.resolve.java.wrapper.PsiClassWrapper;
 import org.jetbrains.jet.lang.resolve.name.FqName;
+import org.jetbrains.jet.lang.resolve.name.Name;
 import org.jetbrains.jet.lang.resolve.scopes.JetScope;
 
 import javax.inject.Inject;
-import java.util.Collections;
-import java.util.Map;
-import java.util.Set;
+import java.util.*;
 
 import static org.jetbrains.jet.lang.resolve.java.AbiVersionUtil.INVALID_VERSION;
 
@@ -273,4 +272,20 @@ public final class JavaNamespaceResolver {
 
         return false;
     }
+
+    @NotNull
+    public Collection<Name> getClassNamesInPackage(@NotNull FqName packageName) {
+        PsiPackage psiPackage = psiClassFinder.findPsiPackage(packageName);
+        if (psiPackage == null) return Collections.emptyList();
+
+        PsiClass[] classes = psiPackage.getClasses();
+        List<Name> result = new ArrayList<Name>(classes.length);
+        for (PsiClass psiClass : classes) {
+            if (DescriptorResolverUtils.isKotlinClass(psiClass)) {
+                result.add(Name.identifier(psiClass.getName()));
+            }
+        }
+
+        return result;
+    }
 }