Parse documentation for class aliases, fix for /// comments.

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 04486e5594ece7e6786f75cff6fb6434dd6924fb..9458cde75336c55b51ce4e4c030f24de47884895 100644
--- a/pkg/front_end/lib/src/fasta/source/outline_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/outline_builder.dart
@@ -285,13 +285,7 @@ class OutlineBuilder extends UnhandledListener {
       Token implementsKeyword,
       Token endToken) {
     debugEvent("endClassDeclaration");
-
-    String documentationComment = null;
-    if (beginToken.precedingComments != null) {
-      documentationComment = beginToken.precedingComments.lexeme;
-      // TODO(scheglov): Add support for line comments.
-    }
-
+    String documentationComment = _getDocumentationComment(beginToken);
     List<TypeBuilder> interfaces = popList(interfacesCount);
     TypeBuilder supertype = pop();
     List<TypeVariableBuilder> typeVariables = pop();
@@ -464,6 +458,7 @@ class OutlineBuilder extends UnhandledListener {
   void endNamedMixinApplication(Token beginToken, Token classKeyword,
       Token equals, Token implementsKeyword, Token endToken) {
     debugEvent("endNamedMixinApplication");
+    String documentationComment = _getDocumentationComment(beginToken);
     List<TypeBuilder> interfaces = popIfNotNull(implementsKeyword);
     TypeBuilder mixinApplication = pop();
     List<TypeVariableBuilder> typeVariables = pop();
@@ -471,8 +466,8 @@ class OutlineBuilder extends UnhandledListener {
     String name = pop();
     int modifiers = Modifier.validate(pop());
     List<MetadataBuilder> metadata = pop();
-    library.addNamedMixinApplication(metadata, name, typeVariables, modifiers,
-        mixinApplication, interfaces, charOffset);
+    library.addNamedMixinApplication(documentationComment, metadata, name,
+        typeVariables, modifiers, mixinApplication, interfaces, charOffset);
     checkEmpty(beginToken.charOffset);
   }
 
@@ -916,6 +911,34 @@ class OutlineBuilder extends UnhandledListener {
     return removeNativeClause(identifiers, stringExpectedAfterNative);
   }
 
+  /// Return the documentation comment for the entity that starts at the
+  /// given [token], or `null` if there is no preceding documentation comment.
+  String _getDocumentationComment(Token token) {
+    Token docToken = token.precedingComments;
+    if (docToken == null) return null;
+    bool inSlash = false;
+    var buffer = new StringBuffer();
+    while (docToken != null) {
+      String lexeme = docToken.lexeme;
+      if (lexeme.startsWith('/**')) {
+        inSlash = false;
+        buffer.clear();
+        buffer.write(lexeme);
+      } else if (lexeme.startsWith('///')) {
+        if (!inSlash) {
+          inSlash = true;
+          buffer.clear();
+        }
+        if (buffer.isNotEmpty) {
+          buffer.writeln();
+        }
+        buffer.write(lexeme);
+      }
+      docToken = docToken.next;
+    }
+    return buffer.toString();
+  }
+
   @override
   void debugEvent(String name) {
     // printEvent(name);