Hook for overriding the ContextManager and some code clean-up (with more to follow)

pkg/analysis_server/lib/starter.dart

Index: pkg/analysis_server/lib/starter.dart
diff --git a/pkg/analysis_server/lib/starter.dart b/pkg/analysis_server/lib/starter.dart
index e96c8b3d4d3933258e9dba685d3c3672234f2844..87821c144caa61db3699ad689675f050887651d5 100644
--- a/pkg/analysis_server/lib/starter.dart
+++ b/pkg/analysis_server/lib/starter.dart
@@ -4,6 +4,7 @@
 
 library driver;
 
+import 'package:analysis_server/src/context_manager.dart';
 import 'package:analysis_server/src/server/driver.dart';
 import 'package:analysis_server/uri/resolver_provider.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
@@ -19,6 +20,12 @@ abstract class ServerStarter {
   factory ServerStarter() = Driver;
 
   /**
+   * Set the context manager used to create analysis contexts within each of the
+   * analysis roots.
+   */
+  void set contextManager(ContextManager manager);
+
+  /**
    * Set the instrumentation [server] that is to be used by the analysis server.
    */
   void set instrumentationServer(InstrumentationServer server);
@@ -28,6 +35,7 @@ abstract class ServerStarter {
    * are resolved in some contexts. The provider should return `null` if the
    * default package resolution scheme should be used instead.
    */
+  @deprecated
   void set packageResolverProvider(ResolverProvider provider);
 
   /**