Change accessors and AstFactory to use tokens rather than file offsets.

pkg/front_end/lib/src/fasta/kernel/kernel_ast_factory.dart

 // Copyright (c) 2017, 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 file.
 
+import 'package:front_end/src/fasta/kernel/utils.dart';
+import 'package:front_end/src/fasta/scanner/token.dart' show Token;
 import 'package:front_end/src/fasta/type_inference/type_promotion.dart';
 import 'package:kernel/ast.dart';
 
 import '../builder/ast_factory.dart';
 import 'kernel_shadow_ast.dart';
 
 /// Concrete implementation of [builder.AstFactory] for building a kernel AST.
 class KernelAstFactory implements AstFactory<VariableDeclaration> {
   @override
-  KernelBlock block(List<Statement> statements, int charOffset) {
-    return new KernelBlock(statements)..fileOffset = charOffset;
+  KernelBlock block(List<Statement> statements, Token beginToken) {
+    return new KernelBlock(statements)..fileOffset = offsetForToken(beginToken);
   }
 
   @override
   ExpressionStatement expressionStatement(Expression expression) {
     return new KernelExpressionStatement(expression);
   }
 
   @override
   Field field(Name name, int charOffset, {String fileUri}) {
     return new KernelField(name, fileUri: fileUri)..fileOffset = charOffset;
   }
 
   @override
-  FunctionExpression functionExpression(FunctionNode function, int charOffset) {
-    return new KernelFunctionExpression(function)..fileOffset = charOffset;
+  FunctionExpression functionExpression(FunctionNode function, Token token) {
+    return new KernelFunctionExpression(function)
+      ..fileOffset = offsetForToken(token);
   }
 
   @override
   Statement ifStatement(
       Expression condition, Statement thenPart, Statement elsePart) {
     return new KernelIfStatement(condition, thenPart, elsePart);
   }
 
   @override
-  KernelIntLiteral intLiteral(value, int charOffset) {
-    return new KernelIntLiteral(value)..fileOffset = charOffset;
+  KernelIntLiteral intLiteral(value, Token token) {
+    return new KernelIntLiteral(value)..fileOffset = offsetForToken(token);
   }
 
   @override
   Expression isExpression(
-      Expression expression, DartType type, int charOffset, bool isInverted) {
+      Expression expression, DartType type, Token token, bool isInverted) {
     if (isInverted) {
-      return new KernelIsNotExpression(expression, type, charOffset);
+      return new KernelIsNotExpression(expression, type, offsetForToken(token));
     } else {
-      return new KernelIsExpression(expression, type)..fileOffset = charOffset;
+      return new KernelIsExpression(expression, type)
+        ..fileOffset = offsetForToken(token);
     }
   }
 
   @override
   KernelListLiteral listLiteral(List<Expression> expressions,
-      DartType typeArgument, bool isConst, int charOffset) {
+      DartType typeArgument, bool isConst, Token token) {
     return new KernelListLiteral(expressions,
         typeArgument: typeArgument, isConst: isConst)
-      ..fileOffset = charOffset;
+      ..fileOffset = offsetForToken(token);
   }
 
   @override
-  KernelNullLiteral nullLiteral(int charOffset) {
-    return new KernelNullLiteral()..fileOffset = charOffset;
+  KernelNullLiteral nullLiteral(Token token) {
+    return new KernelNullLiteral()..fileOffset = offsetForToken(token);
   }
 
   @override
-  KernelReturnStatement returnStatement(Expression expression, int charOffset) {
-    return new KernelReturnStatement(expression)..fileOffset = charOffset;
+  KernelReturnStatement returnStatement(Expression expression, Token token) {
+    return new KernelReturnStatement(expression)
+      ..fileOffset = offsetForToken(token);
   }
 
   @override
-  StaticGet staticGet(Member readTarget, int offset) {
-    return new KernelStaticGet(readTarget)..fileOffset = offset;
+  StaticGet staticGet(Member readTarget, Token token) {
+    return new KernelStaticGet(readTarget)..fileOffset = offsetForToken(token);
   }
 
   @override
   VariableDeclaration variableDeclaration(
-      String name, int charOffset, int functionNestingLevel,
+      String name, Token token, int functionNestingLevel,
       {DartType type,
       Expression initializer,
-      int equalsCharOffset = TreeNode.noOffset,
+      Token equalsToken,
       bool isFinal: false,
       bool isConst: false}) {
     return new KernelVariableDeclaration(name, functionNestingLevel,
         type: type,
         initializer: initializer,
         isFinal: isFinal,
         isConst: isConst)
-      ..fileOffset = charOffset
-      ..fileEqualsOffset = equalsCharOffset;
+      ..fileOffset = offsetForToken(token)
+      ..fileEqualsOffset = offsetForToken(equalsToken);
   }
 
   @override
   VariableGet variableGet(
       VariableDeclaration variable,
       TypePromotionFact<VariableDeclaration> fact,
       TypePromotionScope scope,
-      int charOffset) {
+      Token token) {
     return new KernelVariableGet(variable, fact, scope)
-      ..fileOffset = charOffset;
+      ..fileOffset = offsetForToken(token);
   }
 }