Share LibrarySpecificUnits when possible

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 9cd12c7c6c0c394ab7d0c5859ae79012e407636d..04cb284e11a2516b0ea4394c8126503a38c1902b 100644
--- a/pkg/analyzer/lib/src/generated/engine.dart
+++ b/pkg/analyzer/lib/src/generated/engine.dart
@@ -2141,6 +2141,11 @@ abstract class InternalAnalysisContext implements AnalysisContext {
   bool aboutToComputeResult(CacheEntry entry, ResultDescriptor result);
 
   /**
+   * Return the canonical instance of the given [target].
+   */
+  AnalysisTarget canonicalizeTarget(AnalysisTarget target);
+
+  /**
    * Return a list containing the sources of the libraries that are exported by
    * the library with the given [source]. The list will be empty if the given
    * source is invalid, if the given source does not represent a library, or if
@@ -2180,6 +2185,12 @@ abstract class InternalAnalysisContext implements AnalysisContext {
   InternalAnalysisContext getContextFor(Source source);
 
   /**
+   * Return a library specific unit representing the given [unit] as analyzed in
+   * the given [library].
+   */
+  LibrarySpecificUnit getLibrarySpecificUnit(Source library, Source unit);
+
+  /**
    * Return a change notice for the given [source], creating one if one does not
    * already exist.
    */