Restore UriReferencedElement and its uri/uriOffset/uriEnd properties.

pkg/analyzer/lib/dart/element/element.dart

Index: pkg/analyzer/lib/dart/element/element.dart
diff --git a/pkg/analyzer/lib/dart/element/element.dart b/pkg/analyzer/lib/dart/element/element.dart
index ae0c19d51245ad8751988300a4c01cd244cefda6..ce89e898f89f7552b1b173f38ab3e590679e51ad 100644
--- a/pkg/analyzer/lib/dart/element/element.dart
+++ b/pkg/analyzer/lib/dart/element/element.dart
@@ -412,7 +412,7 @@ abstract class ClassMemberElement implements Element {
  *
  * Clients may not extend, implement or mix-in this class.
  */
-abstract class CompilationUnitElement implements Element {
+abstract class CompilationUnitElement implements Element, UriReferencedElement {
   /**
    * An empty list of compilation unit elements.
    */
@@ -1161,7 +1161,7 @@ abstract class ExecutableElement implements FunctionTypedElement {
  *
  * Clients may not extend, implement or mix-in this class.
  */
-abstract class ExportElement implements Element {
+abstract class ExportElement implements Element, UriReferencedElement {
   /**
    * An empty list of export elements.
    */
@@ -1349,7 +1349,7 @@ abstract class HideElementCombinator implements NamespaceCombinator {
  *
  * Clients may not extend, implement or mix-in this class.
  */
-abstract class ImportElement implements Element {
+abstract class ImportElement implements Element, UriReferencedElement {
   /**
    * An empty list of import elements.
    */
@@ -1949,6 +1949,31 @@ abstract class TypeParameterizedElement implements Element {
 abstract class UndefinedElement implements Element {}
 
 /**
+ * An element included into a library using some URI.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class UriReferencedElement implements Element {
+  /**
+   * Return the URI that is used to include this element into the enclosing
+   * library, or `null` if this is the defining compilation unit of a library.
+   */
+  String get uri;
+
+  /**
+   * Return the offset of the character immediately following the last character
+   * of this node's URI, or `-1` for synthetic import.
+   */
+  int get uriEnd;
+
+  /**
+   * Return the offset of the URI in the file, or `-1` if this element is
+   * synthetic.
+   */
+  int get uriOffset;
+}
+
+/**
  * A variable. There are more specific subclasses for more specific kinds of
  * variables.
  *