Switch FE to use the libraries.json format.

tools/patch_sdk.dart

 #!/usr/bin/env 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.
 
 /// Command line tool to merge the SDK libraries and our patch files.
 /// This is currently designed as an offline tool, but we could automate it.
 
 import 'dart:io';
 import 'dart:isolate' show RawReceivePort;
@@ skipping 90 matching lines @@
   var outDirUri = Uri.base.resolveUri(new Uri.directory(outDir));
   var sdkOut = path.join(outDir, 'lib');
   var packagesFile = argv[4];
 
   // Parse libraries.dart
   var libContents = readInputFile(path.join(
       sdkLibIn, '_internal', 'sdk_library_metadata', 'lib', 'libraries.dart'));
   libContents = _updateLibraryMetadata(sdkOut, libContents);
   var sdkLibraries = _getSdkLibraries(libContents);
 
-  Map<String, String> locations = <String, String>{};
+  var locations = <String, Map<String, String>>{};
 
   // Enumerate core libraries and apply patches
   for (SdkLibrary library in sdkLibraries) {
     if (forDart2js && library.isVmLibrary) continue;
     if (!forDart2js && library.isDart2JsLibrary) continue;
     _applyPatch(library, sdkLibIn, patchIn, sdkOut, locations);
   }
 
   _copyExtraLibraries(sdkOut, locations);
 
   Uri platform = outDirUri.resolve('platform.dill.tmp');
   Uri outline = outDirUri.resolve('outline.dill');
   Uri librariesJson = outDirUri.resolve("lib/libraries.json");
   Uri packages = Uri.base.resolveUri(new Uri.file(packagesFile));
 
   await _writeSync(
-      librariesJson.toFilePath(), JSON.encode({"libraries": locations}));
+      librariesJson.toFilePath(),
+      JSON.encode({
+        mode: {"libraries": locations}
+      }));
 
   var flags = new TargetFlags();
   var target = forVm
       ? new VmFastaTarget(flags)
       : (forFlutter ? new FlutterFastaTarget(flags) : new Dart2jsTarget(flags));
   var platformDeps =
       await compilePlatform(outDirUri, target, packages, platform, outline);
   deps.addAll(platformDeps);
 
   if (forVm) {
     // TODO(sigmund): add support for the flutter vmservice_sky as well.
     var vmserviceName = 'vmservice_io';
     var base = path.fromUri(Platform.script);
     Uri dartDir =
         new Uri.directory(path.dirname(path.dirname(path.absolute(base))));
+
+    String vmserviceJson = JSON.encode({
+      'vm': {
+        "libraries": {
+          '_vmservice': {
+            'path': dartDir.resolve('sdk/lib/vmservice/vmservice.dart').path
+          },
+          'vmservice_io': {
+            'path':
+                dartDir.resolve('runtime/bin/vmservice/vmservice_io.dart').path
+          },
+        }
+      }
+    });
+    Uri vmserviceJsonUri = outDirUri.resolve("lib/vmservice_libraries.json");
+    await _writeSync(vmserviceJsonUri.toFilePath(), vmserviceJson);
     var program = await kernelForProgram(
         Uri.parse('dart:$vmserviceName'),
         new CompilerOptions()
           ..setExitCodeOnProblem = true
           // TODO(sigmund): investigate. This should be outline, but it breaks
           // vm-debug tests. Issue #30111
           ..sdkSummary = platform
-          ..dartLibraries = <String, Uri>{
-            '_vmservice': dartDir.resolve('sdk/lib/vmservice/vmservice.dart'),
-            'vmservice_io':
-                dartDir.resolve('runtime/bin/vmservice/vmservice_io.dart'),
-          }
+          ..librariesSpecUri = vmserviceJsonUri
           ..packagesFileUri = packages);
     Uri vmserviceUri = outDirUri.resolve('$vmserviceName.dill');
     // TODO(sigmund): remove. This is a workaround because in the VM
     // doesn't support loading vmservice if it contains external libraries
     // (there is an assertion that only fails in debug builds). Issue #30111
     program.libraries.forEach((l) => l.isExternal = false);
     await writeProgramToFile(program, vmserviceUri);
   }
 
   Uri platformFinalLocation = outDirUri.resolve('platform.dill');
@@ skipping 160 matching lines @@
   _writeSync(
       path.join(
           sdkOut, '_internal', 'sdk_library_metadata', 'lib', 'libraries.dart'),
       libContents);
   return libContents;
 }
 
 /// Copy internal libraries that are developed outside the sdk folder into the
 /// patched_sdk folder. For the VM< this includes files under 'runtime/bin/',
 /// for flutter, this is includes also the ui library.
-_copyExtraLibraries(String sdkOut, Map<String, String> locations) {
+_copyExtraLibraries(String sdkOut, Map<String, Map<String, String>> locations) {
   if (forDart2js) return;
   var base = path.fromUri(Platform.script);
   var dartDir = path.dirname(path.dirname(path.absolute(base)));
 
   var builtinLibraryIn = path.join(dartDir, 'runtime', 'bin', 'builtin.dart');
   var builtinLibraryOut = path.join(sdkOut, '_builtin', '_builtin.dart');
   _writeSync(builtinLibraryOut, readInputFile(builtinLibraryIn));
-  locations['_builtin'] = path.join('_builtin', '_builtin.dart');
+  addLocation(locations, '_builtin', path.join('_builtin', '_builtin.dart'));
 
   if (forFlutter) {
     // Flutter repo has this layout:
     //  engine/src/
     //       dart/
     //       flutter/
     var srcDir = path.dirname(path.dirname(path.dirname(path.absolute(base))));
     var uiLibraryInDir = path.join(srcDir, 'flutter', 'lib', 'ui');
     for (var file in new Directory(uiLibraryInDir).listSync()) {
       if (!file.path.endsWith('.dart')) continue;
       var name = path.basename(file.path);
       var uiLibraryOut = path.join(sdkOut, 'ui', name);
       _writeSync(uiLibraryOut, readInputFile(file.path));
     }
-    locations['ui'] = 'ui/ui.dart';
+    addLocation(locations, 'ui', path.join('ui', 'ui.dart'));
 
     if (!forFlutterRelease) {
       // vmservice should be present unless we build release flavor of Flutter.
       //
       // TODO(dartbug.com/30158): Consider producing separate Flutter
       // vmservice.dill with these vmservice libraries.
       for (var file in ['loader.dart', 'server.dart', 'vmservice_io.dart']) {
         var libraryIn = path.join(dartDir, 'runtime', 'bin', 'vmservice', file);
         var libraryOut = path.join(sdkOut, 'vmservice_io', file);
         _writeSync(libraryOut, readInputFile(libraryIn));
       }
-      locations['vmservice_sky'] =
-          path.join('vmservice_io', 'vmservice_io.dart');
-      locations['_vmservice'] = path.join('vmservice', 'vmservice.dart');
+      addLocation(locations, 'vmservice_sky',
+          path.join('vmservice_io', 'vmservice_io.dart'));
+      addLocation(
+          locations, '_vmservice', path.join('vmservice', 'vmservice.dart'));
     }
   }
 }
 
 _applyPatch(SdkLibrary library, String sdkLibIn, String patchIn, String sdkOut,
-    Map<String, String> locations) {
+    Map<String, Map<String, String>> locations) {
   var libraryOut = path.join(sdkLibIn, library.path);
   var libraryIn = libraryOut;
 
   var libraryFile = getInputFile(libraryIn, canBeMissing: true);
   if (libraryFile != null) {
-    locations[Uri.parse(library.shortName).path] =
-        path.relative(libraryOut, from: sdkLibIn);
+    addLocation(locations, Uri.parse(library.shortName).path,
+        path.relative(libraryOut, from: sdkLibIn));
     var outPaths = <String>[libraryOut];
     var libraryContents = libraryFile.readAsStringSync();
 
     int inputModifyTime = libraryFile.lastModifiedSync().millisecondsSinceEpoch;
     var partFiles = <File>[];
     for (var part in parseDirectives(libraryContents).directives) {
       if (part is PartDirective) {
         var partPath = part.uri.stringValue;
         outPaths.add(path.join(path.dirname(libraryOut), partPath));
 
@@ skipping 402 matching lines @@
     if (diff != 0) return diff;
     return end - other.end;
   }
 }
 
 List<SdkLibrary> _getSdkLibraries(String contents) {
   var libraryBuilder = new SdkLibrariesReader_LibraryBuilder(forDart2js);
   parseCompilationUnit(contents).accept(libraryBuilder);
   return libraryBuilder.librariesMap.sdkLibraries;
 }
+
+void addLocation(Map<String, Map<String, String>> locations, String libraryName,
+    String path) {
+  assert(locations[libraryName] == null);
+  locations[libraryName] = {'path': path};
+}