Change analysis server protocol to omit empty lists when optional.

editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/generated/types/SearchResult.java

Index: editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/generated/types/SearchResult.java
diff --git a/editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/generated/types/SearchResult.java b/editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/generated/types/SearchResult.java
index 10712f2a1ca5d5e99abe0c8ffc6400b2e7521494..350eee4a567b9917798df9a6fe54391accaf6538 100644
--- a/editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/generated/types/SearchResult.java
+++ b/editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/generated/types/SearchResult.java
@@ -92,7 +92,7 @@ public class SearchResult {
     Location location = Location.fromJson(jsonObject.get("location").getAsJsonObject());
     String kind = jsonObject.get("kind").getAsString();
     Boolean isPotential = jsonObject.get("isPotential").getAsBoolean();
-    List<Element> path = Element.fromJsonArray(jsonObject.get("path").getAsJsonArray());
+    List<Element> path = jsonObject.get("path") == null ? null : Element.fromJsonArray(jsonObject.get("path").getAsJsonArray());
     return new SearchResult(location, kind, isPotential, path);
   }
 
@@ -144,11 +144,13 @@ public class SearchResult {
     jsonObject.add("location", location.toJson());
     jsonObject.addProperty("kind", kind);
     jsonObject.addProperty("isPotential", isPotential);
-    JsonArray jsonArrayPath = new JsonArray();
-    for(Element elt : path) {
-      jsonArrayPath.add(elt.toJson());
+    if (path != null) {
+      JsonArray jsonArrayPath = new JsonArray();
+      for(Element elt : path) {
+        jsonArrayPath.add(elt.toJson());
+      }
+      jsonObject.add("path", jsonArrayPath);
     }
-    jsonObject.add("path", jsonArrayPath);
     return jsonObject;
   }