Fix named parameters handling of values that are falsy in JS.

compiler/javatests/com/google/dart/compiler/common/GenerateSourceMapTest.java

Index: compiler/javatests/com/google/dart/compiler/common/GenerateSourceMapTest.java
===================================================================
--- compiler/javatests/com/google/dart/compiler/common/GenerateSourceMapTest.java	(revision 305)
+++ compiler/javatests/com/google/dart/compiler/common/GenerateSourceMapTest.java	(working copy)
@@ -296,12 +296,16 @@
       case DART:
         return getResultForCompile(filename, sourceCode, part, new DartBackend(),
             DartBackend.EXTENSION_DART, DartBackend.EXTENSION_DART_SRC_MAP);
-      case JS:
-        return getResultForCompile(filename, sourceCode, part, new JavascriptBackend(),
+      case JS: {
+        JavascriptBackend backend = new JavascriptBackend();
+        return getResultForCompile(filename, sourceCode, part, backend,

[jat, 2011/10/11 20:28:23]

Is there some reason for extracting the backend variable?  Or was this just for
debugging?

[John Lenz, 2011/10/11 20:35:55]

reverted.

             JavascriptBackend.EXTENSION_JS, JavascriptBackend.EXTENSION_JS_SRC_MAP);
-      case CLOSURE_JS:
-        return getResultForCompile(filename, sourceCode, part, new ClosureJsBackend(),
+      }
+      case CLOSURE_JS: {
+        ClosureJsBackend backend = new ClosureJsBackend();
+        return getResultForCompile(filename, sourceCode, part, backend,
             ClosureJsBackend.EXTENSION_JS, ClosureJsBackend.EXTENSION_JS_SRC_MAP);
+      }
     }
     throw new IllegalStateException();
   }