Use messages for (some) public API errors

pkg/front_end/lib/src/kernel_generator_impl.dart

Index: pkg/front_end/lib/src/kernel_generator_impl.dart
diff --git a/pkg/front_end/lib/src/kernel_generator_impl.dart b/pkg/front_end/lib/src/kernel_generator_impl.dart
index fca3fb1e35b08c639ed839a0d517d914ee55bb88..f12a61450ba3313d208c5edfc8433108b060b9da 100644
--- a/pkg/front_end/lib/src/kernel_generator_impl.dart
+++ b/pkg/front_end/lib/src/kernel_generator_impl.dart
@@ -11,13 +11,13 @@ import 'dart:async';
 import 'package:kernel/kernel.dart' show Program, CanonicalName;
 
 import 'base/processed_options.dart';
+import 'fasta/compiler_command_line.dart';
 import 'fasta/dill/dill_target.dart' show DillTarget;
 import 'fasta/deprecated_problems.dart' show deprecated_InputError, reportCrash;
 import 'fasta/kernel/kernel_outline_shaker.dart';
 import 'fasta/kernel/kernel_target.dart' show KernelTarget;
-import 'fasta/kernel/verifier.dart';
 import 'fasta/kernel/utils.dart';
-import 'fasta/compiler_command_line.dart';
+import 'fasta/kernel/verifier.dart';
 import 'fasta/translate_uri.dart' show TranslateUri;
 
 /// Implementation for the `package:front_end/kernel_generator.dart` and
@@ -110,7 +110,7 @@ Future<CompilerResult> generateKernelInternal(ProcessedOptions options,
         trimProgram(summaryProgram, (uri) => !excluded.contains(uri));
       }
       if (options.verify) {
-        verifyProgram(summaryProgram).forEach((e) => options.reportError('$e'));
+        verifyProgram(summaryProgram).forEach(options.reportMessage);
       }
       if (options.debugDump) {
         printProgramText(summaryProgram,
@@ -137,7 +137,7 @@ Future<CompilerResult> generateKernelInternal(ProcessedOptions options,
     }
 
     if (kernelTarget.errors.isNotEmpty) {
-      kernelTarget.errors.forEach(options.reportError);
+      kernelTarget.errors.forEach(options.deprecated_reportError);
       return null;
     }
 
@@ -146,7 +146,7 @@ Future<CompilerResult> generateKernelInternal(ProcessedOptions options,
         program: program,
         deps: kernelTarget.loader.getDependencies());
   } on deprecated_InputError catch (e) {
-    options.reportError(e.deprecated_format());
+    options.deprecated_reportError(e.deprecated_format());
     return null;
   } catch (e, t) {
     return reportCrash(e, t);