Utilities in JsDescriptorUtils.

Adapted from https://github.com/develar/kotlin/commit/a9e0a42fb1347fa8e21c86b5a073ef8a7c873da0.

js/js.translator/src/org/jetbrains/k2js/translate/utils/JsDescriptorUtils.java

@@ -19,11 +19,19 @@ package org.jetbrains.k2js.translate.utils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.descriptors.*;
+import org.jetbrains.jet.lang.psi.JetExpression;
+import org.jetbrains.jet.lang.resolve.BindingContext;
+import org.jetbrains.jet.lang.resolve.DescriptorUtils;
 import org.jetbrains.jet.lang.resolve.calls.ResolvedCall;
+import org.jetbrains.jet.lang.resolve.name.Name;
 import org.jetbrains.jet.lang.resolve.scopes.receivers.ClassReceiver;
 import org.jetbrains.jet.lang.resolve.scopes.receivers.ExtensionReceiver;
 import org.jetbrains.jet.lang.resolve.scopes.receivers.ReceiverDescriptor;
+import org.jetbrains.jet.lang.types.JetType;
 import org.jetbrains.jet.lang.types.expressions.OperatorConventions;
+import org.jetbrains.jet.lang.types.lang.JetStandardClasses;
+import org.jetbrains.jet.lang.types.lang.JetStandardLibrary;
+import org.jetbrains.k2js.translate.context.TranslationContext;
 
 import java.util.List;
 import java.util.Set;
@@ -145,6 +153,35 @@ public final class JsDescriptorUtils {
                !isDefaultAccessor(propertyDescriptor.getSetter());
     }
 
+    public static boolean isStandardDeclaration(@NotNull DeclarationDescriptor descriptor) {
+        NamespaceDescriptor namespace = getContainingNamespace(descriptor);
+        if (namespace == null) {
+            return false;
+        }
+        return namespace.equals(JetStandardLibrary.getInstance().getLibraryScope().getContainingDeclaration());
+    }
+
+    @Nullable
+    public static NamespaceDescriptor getContainingNamespace(@NotNull DeclarationDescriptor descriptor) {
+        return DescriptorUtils.getParentOfType(descriptor, NamespaceDescriptor.class);
+    }
+
+    @Nullable
+    public static Name getNameIfStandardType(@NotNull JetExpression expression, @NotNull TranslationContext context) {
+        JetType type = context.bindingContext().get(BindingContext.EXPRESSION_TYPE, expression);
+        return type != null ? getNameIfStandardType(type) : null;
+    }
+
+    @Nullable
+    public static Name getNameIfStandardType(@NotNull JetType type) {
+        ClassifierDescriptor descriptor = type.getConstructor().getDeclarationDescriptor();
+        if (descriptor != null && descriptor.getContainingDeclaration() == JetStandardClasses.STANDARD_CLASSES_NAMESPACE) {
+            return descriptor.getName();
+        }
+
+        return null;
+    }
+
     @NotNull
     public static DeclarationDescriptor getDeclarationDescriptorForExtensionCallReceiver(
             @NotNull ResolvedCall<? extends CallableDescriptor> resolvedCall