Add an imported into list for libraries so that it is possible to lookup

vm/raw_object.h

Index: vm/raw_object.h
===================================================================
--- vm/raw_object.h	(revision 591)
+++ vm/raw_object.h	(working copy)
@@ -448,13 +448,16 @@
   RawString* private_key_;
   RawArray* dictionary_;         // Top-level names in this library.
   RawArray* anonymous_classes_;  // Classes containing top-level elements.
-  RawArray* imports_;            // Imported libraries.
+  RawArray* imports_;            // List of libraries imported without prefix.
+  RawArray* imported_into_;      // List of libraries where this library
+                                 // is imported into without a prefix.
   RawLibrary* next_registered_;  // Linked list of registered libraries.
   RawObject** to() {
     return reinterpret_cast<RawObject**>(&ptr()->next_registered_);
   }
 
   intptr_t num_imports_;         // Number of entries in imports_.
+  intptr_t num_imported_into_;   // Number of entries in imported_into_.
   intptr_t num_anonymous_;       // Number of entries in anonymous_classes_.
   Dart_NativeEntryResolver native_entry_resolver_;  // Resolves natives.
   bool corelib_imported_;