Encode URIs stored in unlinked summaries to make them Uri.parse() safe.

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

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library serialization.summarize_ast;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/type.dart' show DartType;
@@ skipping 1288 matching lines @@
       hasCoreBeenImported = true;
     }
     b.offset = node.offset;
     b.combinators = node.combinators.map(serializeCombinator).toList();
     b.configurations = node.configurations.map(serializeConfiguration).toList();
     if (node.prefix != null) {
       b.prefixReference = serializeReference(null, node.prefix.name);
       b.prefixOffset = node.prefix.offset;
     }
     b.isDeferred = node.deferredKeyword != null;
-    b.uri = node.uri.stringValue;
+    b.uri = Uri.encodeFull(node.uri.stringValue ?? '');
     b.uriOffset = node.uri.offset;
     b.uriEnd = node.uri.end;
     unlinkedImports.add(b);
   }
 
   @override
   void visitLabel(Label node) {
     AstNode parent = node.parent;
     if (parent is! NamedExpression) {
       labels.add(new UnlinkedLabelBuilder(
@@ skipping 97 matching lines @@
 /**
  * A [_TypeParameterScope] is a [_Scope] which defines [_ScopedTypeParameter]s.
  */
 class _TypeParameterScope extends _Scope {
   /**
    * Get the number of [_ScopedTypeParameter]s defined in this
    * [_TypeParameterScope].
    */
   int get length => _definedNames.length;
 }