Update imports to use package:compiler and package:try.

dart/tests/compiler/dart2js/memory_source_file_helper.dart

Index: dart/tests/compiler/dart2js/memory_source_file_helper.dart
diff --git a/dart/tests/compiler/dart2js/memory_source_file_helper.dart b/dart/tests/compiler/dart2js/memory_source_file_helper.dart
index db8010d612b0210976bef3d1edff2f3ba25b4244..09d2d86956509c6cbfb430abc8e1fda5af23c94b 100644
--- a/dart/tests/compiler/dart2js/memory_source_file_helper.dart
+++ b/dart/tests/compiler/dart2js/memory_source_file_helper.dart
@@ -7,19 +7,19 @@ library dart2js.test.memory_source_file_helper;
 import 'dart:async' show Future;
 export 'dart:io' show Platform;
 
-export '../../../sdk/lib/_internal/compiler/implementation/apiimpl.dart'
+export 'package:compiler/implementation/apiimpl.dart'
        show Compiler;
 
-export '../../../sdk/lib/_internal/compiler/implementation/filenames.dart'
+export 'package:compiler/implementation/filenames.dart'
        show currentDirectory;
 
-import '../../../sdk/lib/_internal/compiler/implementation/source_file.dart'
+import 'package:compiler/implementation/source_file.dart'
        show StringSourceFile;
 
-import '../../../sdk/lib/_internal/compiler/implementation/source_file_provider.dart'
+import 'package:compiler/implementation/source_file_provider.dart'
        show SourceFileProvider;
 
-export '../../../sdk/lib/_internal/compiler/implementation/source_file_provider.dart'
+export 'package:compiler/implementation/source_file_provider.dart'
        show SourceFileProvider, FormattingDiagnosticHandler;
 
 class MemorySourceFileProvider extends SourceFileProvider {