Support for replacing of the context folder.

pkg/analysis_server/lib/src/context_manager.dart

Index: pkg/analysis_server/lib/src/context_manager.dart
diff --git a/pkg/analysis_server/lib/src/context_manager.dart b/pkg/analysis_server/lib/src/context_manager.dart
index 3afe0f2423e2102becdcfdcd9dec03c8c55430f4..a87fdc546126042aa999be776648881e43167456 100644
--- a/pkg/analysis_server/lib/src/context_manager.dart
+++ b/pkg/analysis_server/lib/src/context_manager.dart
@@ -335,6 +335,12 @@ abstract class ContextManagerCallbacks {
   void computingPackageMap(bool computing);
 
   /**
+   * Called when the context manager changes the folder with which a context is
+   * associated. Currently this is mostly FYI, and used only in tests.
+   */
+  void moveContext(Folder from, Folder to);
+
+  /**
    * Remove the context associated with the given [folder].  [flushedFiles] is
    * a list of the files which will be "orphaned" by removing this context
    * (they will no longer be analyzed by any context).