Move flat_buffer and api_signature into front_end.

pkg/analyzer/tool/summary/generate.dart

 // Copyright (c) 2015, 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.
 
 /**
  * This file contains code to generate serialization/deserialization logic for
  * summaries based on an "IDL" description of the summary format (written in
  * stylized Dart).
  *
  * For each class in the "IDL" input, two corresponding classes are generated:
@@ skipping 415 matching lines @@
     }
   }
 
   /**
    * Entry point to the code generator when generating the "format.dart" file.
    */
   void generateFormatCode() {
     outputHeader();
     out('library analyzer.src.summary.format;');
     out();
-    out("import 'flat_buffers.dart' as fb;");
+    out("import 'dart:convert' as convert;");
+    out();
+    out("import 'package:front_end/src/base/api_signature.dart' as api_sig;");
+    out("import 'package:front_end/src/base/flat_buffers.dart' as fb;");
+    out();
     out("import 'idl.dart' as idl;");
-    out("import 'dart:convert' as convert;");
-    out("import 'api_signature.dart' as api_sig;");
     out();
     for (idlModel.EnumDeclaration enm in _idl.enums.values) {
       _generateEnumReader(enm);
       out();
     }
     for (idlModel.ClassDeclaration cls in _idl.classes.values) {
       _generateBuilder(cls);
       out();
       if (cls.isTopLevel) {
         _generateReadFunction(cls);
@@ skipping 555 matching lines @@
       Token token = comment.tokens.first;
       return token.lexeme.split('\n').map((String line) {
         line = line.trimLeft();
         if (line.startsWith('*')) line = ' ' + line;
         return line;
       }).join('\n');
     }
     return null;
   }
 }