Remove the unused class SingleContextManager

pkg/analysis_server/lib/src/socket_server.dart

Index: pkg/analysis_server/lib/src/socket_server.dart
diff --git a/pkg/analysis_server/lib/src/socket_server.dart b/pkg/analysis_server/lib/src/socket_server.dart
index a7e6bef0d14cee87d2c408e794e79f836f3a29b2..6bef4d8e37e5bd013fde8ab3068be1d3f70c9bed 100644
--- a/pkg/analysis_server/lib/src/socket_server.dart
+++ b/pkg/analysis_server/lib/src/socket_server.dart
@@ -36,7 +36,6 @@ class SocketServer {
   final ServerPlugin serverPlugin;
   final ResolverProvider fileResolverProvider;
   final ResolverProvider packageResolverProvider;
-  final bool useSingleContextManager;
 
   /**
    * The analysis server that was created when a client established a
@@ -57,8 +56,7 @@ class SocketServer {
       this.diagnosticServer,
       this.serverPlugin,
       this.fileResolverProvider,
-      this.packageResolverProvider,
-      this.useSingleContextManager);
+      this.packageResolverProvider);
 
   /**
    * Create an analysis server which will communicate with the client using the
@@ -98,7 +96,6 @@ class SocketServer {
         diagnosticServer: diagnosticServer,
         fileResolverProvider: fileResolverProvider,
         packageResolverProvider: packageResolverProvider,
-        useSingleContextManager: useSingleContextManager,
         rethrowExceptions: false);
     analysisServer.userDefinedPlugins = userDefinedPlugins;
   }