Add stopgap for angular autocompletion.

pkg/analysis_server/lib/src/domain_completion.dart

Index: pkg/analysis_server/lib/src/domain_completion.dart
diff --git a/pkg/analysis_server/lib/src/domain_completion.dart b/pkg/analysis_server/lib/src/domain_completion.dart
index 916b20e7f4e4f2a72b50166864c236d1d00a4c1c..0bc5c9c0403c031eb7714b7eebdf1bbefe19f06a 100644
--- a/pkg/analysis_server/lib/src/domain_completion.dart
+++ b/pkg/analysis_server/lib/src/domain_completion.dart
@@ -91,7 +91,6 @@ class CompletionDomainHandler implements RequestHandler {
       }
       performance.logElapseTime(contributorTag);
     }
-
     performance.logElapseTime(COMPUTE_SUGGESTIONS_TAG);
 
     // TODO (danrubel) if request is obsolete
@@ -139,8 +138,15 @@ class CompletionDomainHandler implements RequestHandler {
       result = await server.getAnalysisResult(params.file);
 
       if (result == null || !result.exists) {
-        server.sendResponse(new Response.unknownSource(request));
-        return;
+        if (server.onNoAnalysisCompletion != null) {
+          String completionId = (_nextCompletionId++).toString();
+          await server.onNoAnalysisCompletion(
+              request, this, params, performance, completionId);
+          return;
+        } else {
+          server.sendResponse(new Response.unknownSource(request));
+          return;
+        }
       }
 
       if (params.offset < 0 || params.offset > result.content.length) {
@@ -187,10 +193,10 @@ class CompletionDomainHandler implements RequestHandler {
         params.offset,
         performance,
         server.ideOptions);
+
     String completionId = (_nextCompletionId++).toString();
 
-    _abortCurrentRequest();
-    _currentRequest = completionRequest;
+    setNewRequest(completionRequest);
 
     // initial response without results
     server.sendResponse(new CompletionGetSuggestionsResult(completionId)
@@ -203,19 +209,27 @@ class CompletionDomainHandler implements RequestHandler {
       sendCompletionNotification(completionId, result.replacementOffset,
           result.replacementLength, result.suggestions);
       performance.logElapseTime(SEND_NOTIFICATION_TAG);
-
       performance.notificationCount = 1;
       performance.logFirstNotificationComplete('notification 1 complete');
       performance.suggestionCountFirst = result.suggestions.length;
       performance.suggestionCountLast = result.suggestions.length;
       performance.complete();
     }).whenComplete(() {
-      if (_currentRequest == completionRequest) {
-        _currentRequest = null;
-      }
+      ifMatchesRequestClear(completionRequest);
     });
   }
 
+  void setNewRequest(CompletionRequest completionRequest) {
+    _abortCurrentRequest();
+    _currentRequest = completionRequest;
+  }
+
+  void ifMatchesRequestClear(CompletionRequest completionRequest) {
+    if (_currentRequest == completionRequest) {
+      _currentRequest = null;
+    }
+  }
+
   /**
    * If tracking code completion performance over time, then
    * record addition information about the request in the performance record.