Revert last 4 commits by lrn@

pkg/front_end/lib/src/fasta/parser/parser.dart

Index: pkg/front_end/lib/src/fasta/parser/parser.dart
diff --git a/pkg/front_end/lib/src/fasta/parser/parser.dart b/pkg/front_end/lib/src/fasta/parser/parser.dart
index 186f8965fcc3c851c5270e50e3673ea133960c0c..1eda2a6d2be3129b4d48e726f090f6e5f2672d16 100644
--- a/pkg/front_end/lib/src/fasta/parser/parser.dart
+++ b/pkg/front_end/lib/src/fasta/parser/parser.dart
@@ -344,13 +344,8 @@ class Parser {
     assert(optional('part', token));
     assert(optional('of', token.next));
     Token partKeyword = token;
-    token = token.next.next;
-    if (token.isIdentifier()) {
-      token = parseQualified(token, IdentifierContext.partName,
-            IdentifierContext.partNameContinuation);
-    } else {
-      token = parseLiteralStringOrRecoverExpression(token);
-    }
+    token = parseQualified(token.next.next, IdentifierContext.partName,
+        IdentifierContext.partNameContinuation);
     Token semicolon = token;
     token = expect(';', token);
     listener.endPartOf(partKeyword, semicolon);