tools/gn: don't allow trailing junk or non-literals in "value" conversion

tools/gn/input_conversion.cc

Index: tools/gn/input_conversion.cc
diff --git a/tools/gn/input_conversion.cc b/tools/gn/input_conversion.cc
index 6369d2dbfa1e7accb8f43a1d8ae0d8f4b13eb0c0..3d9d355c8a346c3e38be5bff40cceabb45aa4d06 100644
--- a/tools/gn/input_conversion.cc
+++ b/tools/gn/input_conversion.cc
@@ -59,7 +59,7 @@ Value ParseValueOrScope(const Settings* settings,
 
   // Parse the file according to what we're looking for.
   if (what == PARSE_VALUE)
-    *parse_root_ptr = Parser::ParseExpression(*tokens, err);
+    *parse_root_ptr = Parser::ParseValue(*tokens, err);
   else
     *parse_root_ptr = Parser::Parse(*tokens, err);  // Will return a Block.
   if (err->has_error())
@@ -71,15 +71,7 @@ Value ParseValueOrScope(const Settings* settings,
   if (!parse_root)
     return Value();
 
-  // When parsing as a value, the result should either be a list or a literal,
-  // anything else is invalid.
-  if (what == PARSE_VALUE) {
-    if (!parse_root->AsList() && !parse_root->AsLiteral())
-      return Value();
-  }
-
   scoped_ptr<Scope> scope(new Scope(settings));
-
   Value result = parse_root->Execute(scope.get(), err);
   if (err->has_error())
     return Value();