Remove BuilderContext from summary builders.

pkg/analyzer/lib/src/summary/base.dart

Index: pkg/analyzer/lib/src/summary/base.dart
diff --git a/pkg/analyzer/lib/src/summary/base.dart b/pkg/analyzer/lib/src/summary/base.dart
index 0002dc963b7dbc094c8afd3549ec92dc04812461..a04476bcab54e72ff300c47afdff564dd138bdbe 100644
--- a/pkg/analyzer/lib/src/summary/base.dart
+++ b/pkg/analyzer/lib/src/summary/base.dart
@@ -8,20 +8,6 @@
 library analyzer.src.summary.base;
 
 /**
- * Instances of this class encapsulate the necessary state to keep track of a
- * serialized summary that is in the process of being built.
- *
- * This class is intended to be passed to the constructors of the summary
- * Builder classes.
- */
-class BuilderContext {
-  // Note: at the moment this is a placeholder class since the current
-  // serialization format (JSON) doesn't require any state tracking.  If/when
-  // we switch to a serialization format that requires state tracking, the
-  // state will be stored here.
-}
-
-/**
  * Instances of this class represent data that has been read from a summary.
  */
 abstract class SummaryClass {