Initial implementation of MemoryIndexStoreImpl and IndexContributor.

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/index/IndexImpl.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/index/IndexImpl.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/index/IndexImpl.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/index/IndexImpl.java
index d0255ff9e36a077541530366be825b465328051d..2a57ac18ac26a59618ee6ec97988097c6052ec76 100644
--- a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/index/IndexImpl.java
+++ b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/index/IndexImpl.java
@@ -14,7 +14,7 @@
 package com.google.dart.engine.internal.index;
 
 import com.google.dart.engine.ast.CompilationUnit;
-import com.google.dart.engine.element.ElementLocation;
+import com.google.dart.engine.element.ElementProxy;
 import com.google.dart.engine.index.Index;
 import com.google.dart.engine.index.IndexStore;
 import com.google.dart.engine.index.Relationship;
@@ -41,9 +41,9 @@ public class IndexImpl implements Index {
   }
 
   @Override
-  public void getRelationships(ElementLocation elementLocation, Relationship relationship,
+  public void getRelationships(ElementProxy element, Relationship relationship,
       RelationshipCallback callback) {
-    queue.enqueue(new GetRelationshipsOperation(store, elementLocation, relationship, callback));
+    queue.enqueue(new GetRelationshipsOperation(store, element, relationship, callback));
   }
 
   @Override