Refactor SourceFile, SourceFileProvider and SourceLocation.

pkg/compiler/lib/src/io/code_output.dart

Index: pkg/compiler/lib/src/io/code_output.dart
diff --git a/pkg/compiler/lib/src/io/code_output.dart b/pkg/compiler/lib/src/io/code_output.dart
index 5f131987eb33309218426bc141f985c77694f02f..d046f2242a50025c403984b68cae5d28e98e2c60 100644
--- a/pkg/compiler/lib/src/io/code_output.dart
+++ b/pkg/compiler/lib/src/io/code_output.dart
@@ -10,7 +10,7 @@ import 'source_information.dart';
 
 class CodeOutputMarker {
   final int offsetDelta;
-  final SourceFileLocation sourcePosition;
+  final SourceLocation sourcePosition;
 
   CodeOutputMarker(this.offsetDelta, this.sourcePosition);
 }
@@ -43,7 +43,7 @@ abstract class CodeOutput {
 
   /// Applies [f] to every marker in this output.
   void forEachSourceLocation(void f(int targetOffset,
-                                    SourceFileLocation sourceLocation));
+                                    SourceLocation sourceLocation));
 }
 
 abstract class AbstractCodeOutput extends CodeOutput {
@@ -91,7 +91,7 @@ abstract class AbstractCodeOutput extends CodeOutput {
     --mappedRangeCounter;
   }
 
-  void setSourceLocation(SourceFileLocation sourcePosition) {
+  void setSourceLocation(SourceLocation sourcePosition) {
     if (sourcePosition == null) {
       if (markers.length > 0 && markers.last.sourcePosition == null) return;
     }