Clone SourceFactory to ensure that it does not bring a ContentAnalysis reference.

pkg/analyzer/lib/src/dart/analysis/driver.dart

Index: pkg/analyzer/lib/src/dart/analysis/driver.dart
diff --git a/pkg/analyzer/lib/src/dart/analysis/driver.dart b/pkg/analyzer/lib/src/dart/analysis/driver.dart
index 69040333d01abc4676dcaa56bd2e359b3c2bd133..6677376eb6194c04a09169e52b31f29eb282102f 100644
--- a/pkg/analyzer/lib/src/dart/analysis/driver.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/driver.dart
@@ -177,8 +177,9 @@ class AnalysisDriver {
   AnalysisStatus _currentStatus = AnalysisStatus.IDLE;
 
   AnalysisDriver(this._logger, this._resourceProvider, this._byteStore,
-      this._contentCache, this._sourceFactory, this._analysisOptions) {
-    _sdkBundle = _sourceFactory.dartSdk.getLinkedBundle();
+      this._contentCache, SourceFactory sourceFactory, this._analysisOptions)
+      : _sourceFactory = sourceFactory.clone() {

[Brian Wilkerson, 2016/10/31 13:16:57]

It seems to me that this ought to be the responsibility of the client, and that
putting this here adds a performance burden that will be paid by all clients
even if they don't need it. Granted that the cost is low, but the principle is
still the same.

+    _sdkBundle = sourceFactory.dartSdk.getLinkedBundle();
   }
 
   /**