Enable SDK summaries with --enable-new-analysis-driver flag.

pkg/analysis_server/lib/src/server/driver.dart

Index: pkg/analysis_server/lib/src/server/driver.dart
diff --git a/pkg/analysis_server/lib/src/server/driver.dart b/pkg/analysis_server/lib/src/server/driver.dart
index df6df7bc05dddf31ec8f90225ee76eabc553da8c..051ae236bdad55a1764c5dd5a06faa18df60d142 100644
--- a/pkg/analysis_server/lib/src/server/driver.dart
+++ b/pkg/analysis_server/lib/src/server/driver.dart
@@ -389,7 +389,7 @@ class Driver implements ServerStarter {
     analysisServerOptions.enableIncrementalResolutionValidation =
         results[INCREMENTAL_RESOLUTION_VALIDATION];
     analysisServerOptions.enableNewAnalysisDriver =
-      results[ENABLE_NEW_ANALYSIS_DRIVER];
+        results[ENABLE_NEW_ANALYSIS_DRIVER];
     analysisServerOptions.enablePubSummaryManager =
         results[ENABLE_PUB_SUMMARY_MANAGER];
     analysisServerOptions.finerGrainedInvalidation =
@@ -428,7 +428,8 @@ class Driver implements ServerStarter {
           .defaultSdkDirectory(PhysicalResourceProvider.INSTANCE)
           .path;
     }
-    bool useSummaries = analysisServerOptions.fileReadMode == 'as-is';
+    bool useSummaries = analysisServerOptions.fileReadMode == 'as-is' ||
+        analysisServerOptions.enableNewAnalysisDriver;
     // TODO(brianwilkerson) It would be nice to avoid creating an SDK that
     // cannot be re-used, but the SDK is needed to create a package map provider
     // in the case where we need to run `pub` in order to get the package map.