Rename TranslateUri to UriTranslator, rename files, extract Impl.

pkg/front_end/test/fasta/testing/suite.dart

Index: pkg/front_end/test/fasta/testing/suite.dart
diff --git a/pkg/front_end/test/fasta/testing/suite.dart b/pkg/front_end/test/fasta/testing/suite.dart
index 53ddb7a49cbecf7318a38eef16512ecc9ac055b0..026750d54bef145ffd118f2169c538010b7d7bc5 100644
--- a/pkg/front_end/test/fasta/testing/suite.dart
+++ b/pkg/front_end/test/fasta/testing/suite.dart
@@ -17,6 +17,7 @@ import 'package:front_end/src/fasta/testing/validating_instrumentation.dart'
 
 import 'package:front_end/src/fasta/testing/patched_sdk_location.dart'
     show computeDartVm, computePatchedSdk;
+import 'package:front_end/src/fasta/uri_translator_impl.dart';
 
 import 'package:kernel/ast.dart' show Library, Program;
 
@@ -40,7 +41,7 @@ import 'package:front_end/src/fasta/testing/kernel_chain.dart'
 
 import 'package:front_end/src/fasta/ticker.dart' show Ticker;
 
-import 'package:front_end/src/fasta/translate_uri.dart' show TranslateUri;
+import 'package:front_end/src/fasta/uri_translator.dart' show UriTranslator;
 
 import 'package:analyzer/src/fasta/analyzer_target.dart' show AnalyzerTarget;
 
@@ -92,7 +93,7 @@ enum AstKind {
 }
 
 class FastaContext extends ChainContext {
-  final TranslateUri uriTranslator;
+  final UriTranslatorImpl uriTranslator;
   final List<Step> steps;
   final Uri vm;
   final Map<Program, KernelTarget> programToTarget = <Program, KernelTarget>{};
@@ -153,7 +154,7 @@ class FastaContext extends ChainContext {
     Uri sdk = await computePatchedSdk();
     Uri vm = computeDartVm(sdk);
     Uri packages = Uri.base.resolve(".packages");
-    TranslateUri uriTranslator = await TranslateUri
+    UriTranslator uriTranslator = await UriTranslatorImpl
         .parse(PhysicalFileSystem.instance, sdk, packages: packages);
     bool strongMode = environment.containsKey(STRONG_MODE);
     bool updateExpectations = environment["updateExpectations"] == "true";
@@ -236,8 +237,10 @@ class Outline extends Step<TestDescription, Program, FastaContext> {
     dillTarget.loader.appendLibraries(platformOutline);
     // We create a new URI translator to avoid reading platform libraries from
     // file system.
-    TranslateUri uriTranslator = new TranslateUri(const <String, Uri>{},
-        const <String, List<Uri>>{}, context.uriTranslator.packages);
+    UriTranslatorImpl uriTranslator = new UriTranslatorImpl(
+        const <String, Uri>{},
+        const <String, List<Uri>>{},
+        context.uriTranslator.packages);
     KernelTarget sourceTarget = astKind == AstKind.Analyzer
         ? new AnalyzerTarget(dillTarget, uriTranslator, strongMode)
         : new KernelTarget(