update setAnalysisRoots to accept package spec file

pkg/analysis_server/lib/plugin/protocol/generated_protocol.dart

 // Copyright (c) 2014, 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 has been automatically generated.  Please do not edit it manually.
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
 part of analysis_server.plugin.protocol.protocol;
 
@@ skipping 1645 matching lines @@
   /**
    * A list of the files and directories within the included directories that
    * should not be analyzed.
    */
   void set excluded(List<String> value) {
     assert(value != null);
     this._excluded = value;
   }
 
   /**
-   * A mapping from source directories to target directories that should
-   * override the normal package: URI resolution mechanism. The analyzer will
-   * behave as though each source directory in the map contains a special
-   * pubspec.yaml file which resolves any package: URI to the corresponding
-   * path within the target directory. The effect is the same as specifying the
-   * target directory as a "--package_root" parameter to the Dart VM when
+   * A mapping from source directories to package roots that should override
+   * the normal package: URI resolution mechanism.
+   *
+   * If a package root is a directory, then the analyzer will behave as though
+   * the associated source directory in the map contains a special pubspec.yaml
+   * file which resolves any package: URI to the corresponding path within that
+   * package root directory. The effect is the same as specifying the package
+   * root directory as a "--package_root" parameter to the Dart VM when
+   * executing any Dart file inside the source directory.
+   *
+   * If a package root is a file, then the analyzer will behave as though that
+   * file is a ".packages" file in the source directory. The effect is the same
+   * as specifying the file as a "--packages" parameter to the Dart VM when
    * executing any Dart file inside the source directory.
    *
    * Files in any directories that are not overridden by this mapping have
    * their package: URI's resolved using the normal pubspec.yaml mechanism. If
    * this field is absent, or the empty map is specified, that indicates that
    * the normal pubspec.yaml mechanism should always be used.
    */
   Map<String, String> get packageRoots => _packageRoots;
 
   /**
-   * A mapping from source directories to target directories that should
-   * override the normal package: URI resolution mechanism. The analyzer will
-   * behave as though each source directory in the map contains a special
-   * pubspec.yaml file which resolves any package: URI to the corresponding
-   * path within the target directory. The effect is the same as specifying the
-   * target directory as a "--package_root" parameter to the Dart VM when
+   * A mapping from source directories to package roots that should override
+   * the normal package: URI resolution mechanism.
+   *
+   * If a package root is a directory, then the analyzer will behave as though
+   * the associated source directory in the map contains a special pubspec.yaml
+   * file which resolves any package: URI to the corresponding path within that
+   * package root directory. The effect is the same as specifying the package
+   * root directory as a "--package_root" parameter to the Dart VM when
+   * executing any Dart file inside the source directory.
+   *
+   * If a package root is a file, then the analyzer will behave as though that
+   * file is a ".packages" file in the source directory. The effect is the same
+   * as specifying the file as a "--packages" parameter to the Dart VM when
    * executing any Dart file inside the source directory.
    *
    * Files in any directories that are not overridden by this mapping have
    * their package: URI's resolved using the normal pubspec.yaml mechanism. If
    * this field is absent, or the empty map is specified, that indicates that
    * the normal pubspec.yaml mechanism should always be used.
    */
   void set packageRoots(Map<String, String> value) {
     this._packageRoots = value;
   }
@@ skipping 15196 matching lines @@
     return false;
   }
 
   @override
   int get hashCode {
     int hash = 0;
     hash = JenkinsSmiHash.combine(hash, newName.hashCode);
     return JenkinsSmiHash.finish(hash);
   }
 }