Pass 'classKeyword' to endClassDeclaratio() and endNamedMixinApplication().

pkg/front_end/lib/src/fasta/source/outline_builder.dart

Index: pkg/front_end/lib/src/fasta/source/outline_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/source/outline_builder.dart b/pkg/front_end/lib/src/fasta/source/outline_builder.dart
index 90f48f5eb8695d11bd23a19505524f462a9b7c44..a5d08dd00323c0a8d710fdd8d2507f562f32b250 100644
--- a/pkg/front_end/lib/src/fasta/source/outline_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/outline_builder.dart
@@ -204,7 +204,8 @@ class OutlineBuilder extends UnhandledListener {
 
   @override
   void endClassDeclaration(int interfacesCount, Token beginToken,
-      Token extendsKeyword, Token implementsKeyword, Token endToken) {
+      Token classKeyword, Token extendsKeyword, Token implementsKeyword,
+      Token endToken) {
     debugEvent("endClassDeclaration");
     List<TypeBuilder> interfaces = popList(interfacesCount);
     TypeBuilder supertype = pop();
@@ -319,8 +320,8 @@ class OutlineBuilder extends UnhandledListener {
 
   @override
   void endNamedMixinApplication(
-      Token classKeyword, Token equals, Token implementsKeyword,
-      Token endToken) {
+      Token beginToken, Token classKeyword, Token equals,
+      Token implementsKeyword, Token endToken) {
     debugEvent("endNamedMixinApplication");
     List<TypeBuilder> interfaces = popIfNotNull(implementsKeyword);
     TypeBuilder mixinApplication = pop();
@@ -334,8 +335,8 @@ class OutlineBuilder extends UnhandledListener {
     List<MetadataBuilder> metadata = pop();
     library.addNamedMixinApplication(
         metadata, name, typeVariables, modifiers, mixinApplication, interfaces,
-        classKeyword.charOffset);
-    checkEmpty(classKeyword.charOffset);
+        beginToken.charOffset);
+    checkEmpty(beginToken.charOffset);
   }
 
   @override