Revert my last change.

runtime/vm/object.cc

Index: runtime/vm/object.cc
===================================================================
--- runtime/vm/object.cc	(revision 7756)
+++ runtime/vm/object.cc	(working copy)
@@ -4589,6 +4589,11 @@
 }
 
 
+void Library::set_import_map(const Array& map) const {
+  StorePointer(&raw_ptr()->import_map_, map.raw());
+}
+
+
 void Library::SetName(const String& name) const {
   // Only set name once.
   ASSERT(!Loaded());
@@ -5190,6 +5195,23 @@
 }
 
 
+RawString* Library::LookupImportMap(const String& ident) const {
+  Array& import_map = Array::Handle(this->import_map());
+  intptr_t length = import_map.Length();
+  intptr_t index = 0;
+  String& name = String::Handle();
+  while (index < (length - 1)) {
+    name ^= import_map.At(index);
+    if (name.Equals(ident)) {
+      name ^= import_map.At(index + 1);
+      return name.raw();
+    }
+    index += 2;
+  }
+  return String::null();
+}
+
+
 void Library::AddImport(const Library& library) const {
   Array& imports = Array::Handle(this->imports());
   intptr_t capacity = imports.Length();
@@ -5265,6 +5287,7 @@
   result.raw_ptr()->dictionary_ = Array::Empty();
   result.raw_ptr()->anonymous_classes_ = Array::Empty();
   result.raw_ptr()->num_anonymous_ = 0;
+  result.raw_ptr()->import_map_ = Array::Empty();
   result.raw_ptr()->imports_ = Array::Empty();
   result.raw_ptr()->next_registered_ = Library::null();
   result.raw_ptr()->loaded_scripts_ = Array::null();