Allow const factory on methods in parser

compiler/java/com/google/dart/compiler/parser/DartParser.java

Index: compiler/java/com/google/dart/compiler/parser/DartParser.java
diff --git a/compiler/java/com/google/dart/compiler/parser/DartParser.java b/compiler/java/com/google/dart/compiler/parser/DartParser.java
index a840361747924ee7b1876a7779df48c423efbe1f..75459e805df70630d2b9c0eeb231458be8485537 100644
--- a/compiler/java/com/google/dart/compiler/parser/DartParser.java
+++ b/compiler/java/com/google/dart/compiler/parser/DartParser.java
@@ -930,6 +930,10 @@ public class DartParser extends CompletionHooksParserBase {
       case CONST: {
         consume(Token.CONST);
         modifiers = modifiers.makeConstant();
+        // Allow "const factory ... native" constructors for core libraries only
+        if (optionalPseudoKeyword(FACTORY_KEYWORD)) {
+          modifiers = modifiers.makeFactory();
+        }

[srdjan, 2012/03/14 00:41:22]

I do not understand the code completely. Does it guarantee that only native
factories can be const? Non-native factories are not allowed to be const.

[zundel, 2012/03/14 00:43:43]

I added the 'native' check in the resolver in a previous patch to Resolver.java.
 This was enough to allow frog code to parse because it never used the 'factory'
modifier on native constructors.  I forgot to allow both 'const' and 'factory'
modifiers in the parse stage.

         member = done(parseMethod(modifiers, null));
         break;
       }