Allow binary-only references for compile-time constants.

Like we do for binary-only annotations, this change allows binary-only references for compile-time constants.  We don't actually need source in the GWT compiler, JDT embeds the constant value in the unit we do compile.

http://gwt-code-reviews.appspot.com/1447825/

Review by: zundel@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10329 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/dev/core/src/com/google/gwt/dev/javac/BinaryTypeReferenceRestrictionsChecker.java b/dev/core/src/com/google/gwt/dev/javac/BinaryTypeReferenceRestrictionsChecker.java
index 3a36580..569de81 100644
--- a/dev/core/src/com/google/gwt/dev/javac/BinaryTypeReferenceRestrictionsChecker.java
+++ b/dev/core/src/com/google/gwt/dev/javac/BinaryTypeReferenceRestrictionsChecker.java
@@ -22,6 +22,7 @@
 import org.eclipse.jdt.internal.compiler.ast.MarkerAnnotation;
 import org.eclipse.jdt.internal.compiler.ast.NormalAnnotation;
 import org.eclipse.jdt.internal.compiler.ast.SingleMemberAnnotation;
+import org.eclipse.jdt.internal.compiler.impl.Constant;
 import org.eclipse.jdt.internal.compiler.lookup.BinaryTypeBinding;
 import org.eclipse.jdt.internal.compiler.lookup.BlockScope;
 import org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding;
@@ -93,6 +94,10 @@
     @Override
     protected void onBinaryTypeRef(BinaryTypeBinding binding,
         CompilationUnitDeclaration unitOfReferrer, Expression expression) {
+      if (expression.constant != null && expression.constant != Constant.NotAConstant) {
+        // Const expressions are ok, no source needed.
+        return;
+      }
       binaryTypeReferenceSites.add(new BinaryTypeReferenceSite(expression,
           binding));
     }