Minor changes in analyzer to make it easier to extend

pkg/analyzer/lib/src/generated/engine.dart

Index: pkg/analyzer/lib/src/generated/engine.dart
diff --git a/pkg/analyzer/lib/src/generated/engine.dart b/pkg/analyzer/lib/src/generated/engine.dart
index 5b43f575c5b5fd426831897ac44b2a0b00ab9bac..a3d434a5ed417f76068b02a2a5761c288f4b5002 100644
--- a/pkg/analyzer/lib/src/generated/engine.dart
+++ b/pkg/analyzer/lib/src/generated/engine.dart
@@ -1066,6 +1066,12 @@ class AnalysisContextImpl implements InternalAnalysisContext {
    */
   CompilationUnit incrementalResolutionValidation_lastUnit;
 
+  /** A factory to override how [ResolverVisitor] is created. */
+  ResolverVisitorFactory resolverVisitorFactory;
+
+  /** A factory to override how [TypeResolverVisitor] is created. */
+  TypeResolverVisitorFactory typeResolverVisitorFactory;
+
   /**
    * Initialize a newly created analysis context.
    */
@@ -9712,6 +9718,12 @@ abstract class InternalAnalysisContext implements AnalysisContext {
    */
   TypeProvider get typeProvider;
 
+  /** A factory to override how [ResolverVisitor] is created. */
+  ResolverVisitorFactory get resolverVisitorFactory;
+
+  /** A factory to override how [TypeResolverVisitor] is created. */
+  TypeResolverVisitorFactory get typeResolverVisitorFactory;
+
   /**
    * Add the given source with the given information to this context.
    *