Set 'packageResolverProvider' for ContextBuilder in DAS.

pkg/analysis_server/lib/src/analysis_server.dart

Index: pkg/analysis_server/lib/src/analysis_server.dart
diff --git a/pkg/analysis_server/lib/src/analysis_server.dart b/pkg/analysis_server/lib/src/analysis_server.dart
index 12b6378a777afc9892a2cf3881af9bbf8602601f..a5a0ad5ccc91c3dadba3bda78830a878a9107af7 100644
--- a/pkg/analysis_server/lib/src/analysis_server.dart
+++ b/pkg/analysis_server/lib/src/analysis_server.dart
@@ -299,6 +299,12 @@ class AnalysisServer {
   ResolverProvider fileResolverProvider;
 
   /**
+   * The package resolver provider used to override the way package URI's are
+   * resolved in some contexts.
+   */
+  ResolverProvider packageResolverProvider;
+
+  /**
    * The manager of pub package summaries.
    */
   PubSummaryManager pubSummaryManager;
@@ -351,6 +357,7 @@ class AnalysisServer {
           defaultContextOptions);
     }
     this.fileResolverProvider = fileResolverProvider;
+    this.packageResolverProvider = packageResolverProvider;
     ServerContextManagerCallbacks contextManagerCallbacks =
         new ServerContextManagerCallbacks(this, resourceProvider);
     contextManager.callbacks = contextManagerCallbacks;
@@ -1661,6 +1668,7 @@ class ServerContextManagerCallbacks extends ContextManagerCallbacks {
         analysisServer.sdkManager, analysisServer.overlayState);
     builder.defaultOptions = options;
     builder.fileResolverProvider = analysisServer.fileResolverProvider;
+    builder.packageResolverProvider = analysisServer.packageResolverProvider;
     builder.defaultPackageFilePath = defaultPackageFilePath;
     builder.defaultPackagesDirectoryPath = defaultPackagesDirectoryPath;
     return builder;