Move DartWorkManager notification to _sourceChanged().

pkg/analyzer/lib/src/context/context.dart

Index: pkg/analyzer/lib/src/context/context.dart
diff --git a/pkg/analyzer/lib/src/context/context.dart b/pkg/analyzer/lib/src/context/context.dart
index bc3d62f01d6606cfba56f95d21ac85d83c1a9610..f2c54924129c801c35004cbd49dd5cc31af18376 100644
--- a/pkg/analyzer/lib/src/context/context.dart
+++ b/pkg/analyzer/lib/src/context/context.dart
@@ -1171,8 +1171,6 @@ class AnalysisContextImpl implements InternalAnalysisContext {
   @override
   void setContents(Source source, String contents) {
     _contentsChanged(source, contents, true);
-    dartWorkManager.applyChange(
-        Source.EMPTY_LIST, <Source>[source], Source.EMPTY_LIST);
   }
 
   @override
@@ -1693,6 +1691,8 @@ class AnalysisContextImpl implements InternalAnalysisContext {
     }
     // We need to invalidate the cache.
     entry.setState(CONTENT, CacheState.INVALID);
+    dartWorkManager.applyChange(
+        Source.EMPTY_LIST, <Source>[source], Source.EMPTY_LIST);
   }
 
   /**