Revert "Tweak public APIs and use them in patch_sdk, dart2js, and kernel-service."

pkg/front_end/test/fasta/testing/suite.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.md file.
 
 library fasta.testing.suite;
 
 import 'dart:async' show Future;
 
 import 'dart:io' show File;
 
@@ skipping 80 matching lines @@
 }
 
 class FastaContext extends ChainContext {
   final TranslateUri uriTranslator;
   final List<Step> steps;
   final Uri vm;
   final Map<Program, KernelTarget> programToTarget = <Program, KernelTarget>{};
   Uri sdk;
   Uri platformUri;
   Uri outlineUri;
-  Program outline;
+  List<int> outlineBytes;
 
   final ExpectationSet expectationSet =
       new ExpectationSet.fromJsonList(JSON.decode(EXPECTATIONS));
 
   FastaContext(
       this.vm,
       bool strongMode,
       bool updateExpectations,
       bool updateComments,
       bool skipVm,
@@ skipping 20 matching lines @@
 
   Future ensurePlatformUris() async {
     if (sdk == null) {
       sdk = await computePatchedSdk();
       platformUri = sdk.resolve('platform.dill');
       outlineUri = sdk.resolve('outline.dill');
     }
   }
 
   Future<Program> loadPlatformOutline() async {
-    if (outline == null) {
+    if (outlineBytes == null) {
       await ensurePlatformUris();
-      outline =
-          loadProgramFromBytes(new File.fromUri(outlineUri).readAsBytesSync());
+      outlineBytes = new File.fromUri(outlineUri).readAsBytesSync();
     }
-    return outline;
+    // Note: we rebuild the platform outline on every test because the compiler
+    // currently mutates the in-memory representation of the program without
+    // cloning it.
+    // TODO(sigmund): investigate alternatives to this approach.
+    return loadProgramFromBytes(outlineBytes);
   }
 
   static Future<FastaContext> create(
       Chain suite, Map<String, String> environment) async {
     Uri sdk = await computePatchedSdk();
     Uri vm = computeDartVm(sdk);
     Uri packages = Uri.base.resolve(".packages");
     TranslateUri uriTranslator = await TranslateUri
         .parse(PhysicalFileSystem.instance, sdk, packages: packages);
     bool strongMode = environment.containsKey(STRONG_MODE);
@@ skipping 91 matching lines @@
       sourceTarget.read(description.uri);
       await dillTarget.buildOutlines();
       ValidatingInstrumentation instrumentation;
       if (strongMode) {
         instrumentation = new ValidatingInstrumentation();
         await instrumentation.loadExpectations(description.uri);
         sourceTarget.loader.instrumentation = instrumentation;
       }
       p = await sourceTarget.buildOutlines();
       if (fullCompile) {
-        p = await sourceTarget.buildProgram();
+        p = await sourceTarget.buildProgram(trimDependencies: true);
         instrumentation?.finish();
         if (instrumentation != null && instrumentation.hasProblems) {
           if (updateComments) {
             await instrumentation.fixSource(description.uri, false);
           } else {
             return fail(null, instrumentation.problemsAsString);
           }
         }
       }
     } on InputError catch (e, s) {
@@ skipping 43 matching lines @@
     }
   }
 
   void performGlobalTransformations(CoreTypes coreTypes, Program program,
       {void logger(String msg)}) {
     if (enabled) {
       super.performGlobalTransformations(coreTypes, program, logger: logger);
     }
   }
 }