Update the plugin API

pkg/analyzer_plugin/lib/src/utilities/assist/assist.dart

Index: pkg/analyzer_plugin/lib/src/utilities/assist/assist.dart
diff --git a/pkg/analyzer_plugin/lib/src/utilities/assist/assist.dart b/pkg/analyzer_plugin/lib/src/utilities/assist/assist.dart
index 79cdfffc6e9a48257b0b371feb017b8d67ae3d18..ab4578046d32c598f3df4add1798f60746cc3e6a 100644
--- a/pkg/analyzer_plugin/lib/src/utilities/assist/assist.dart
+++ b/pkg/analyzer_plugin/lib/src/utilities/assist/assist.dart
@@ -23,9 +23,9 @@ class AssistCollectorImpl implements AssistCollector {
 }
 
 /**
- * A concrete implementation of [AssistRequest].
+ * A concrete implementation of [DartAssistRequest].
  */
-class AssistRequestImpl implements AssistRequest {
+class DartAssistRequestImpl implements DartAssistRequest {
   @override
   final ResourceProvider resourceProvider;
 
@@ -41,6 +41,6 @@ class AssistRequestImpl implements AssistRequest {
   /**
    * Initialize a newly create request with the given data.
    */
-  AssistRequestImpl(
+  DartAssistRequestImpl(
       this.resourceProvider, this.offset, this.length, this.result);
 }