dart2js: Use frequency of occurence to sort metadata indices.

pkg/compiler/lib/src/js_backend/backend.dart

Index: pkg/compiler/lib/src/js_backend/backend.dart
diff --git a/pkg/compiler/lib/src/js_backend/backend.dart b/pkg/compiler/lib/src/js_backend/backend.dart
index 3bc8c0f28a1957403ca1c30775e7036eedd30d82..6f2e75fac8867c15db6c83ba71eff344995dac31 100644
--- a/pkg/compiler/lib/src/js_backend/backend.dart
+++ b/pkg/compiler/lib/src/js_backend/backend.dart
@@ -212,6 +212,12 @@ class FunctionInlineCache {
   }
 }
 
+class DummyConstantKinds {

[karlklose, 2015/05/28 09:39:52]

I think it use sites of these constants read better if you called the class
'DummyConstantKind' and wrote the constants in all caps.

[herhut, 2015/06/01 12:09:41]

Done.

+  static const String dummyReceiver = "DUMMY_INTERCEPTOR";
+  static const String emptyValue = "EMPTY_VALUE";
+  static const String typeVariableReference = "TYPEVARIALE_REFERENCE";

[sigurdm, 2015/05/27 14:26:41]

DBC: Typo in string

[herhut, 2015/06/01 12:09:41]

Done.

+}
+
 class JavaScriptBackend extends Backend {
   static final Uri DART_JS_HELPER = new Uri(scheme: 'dart', path: '_js_helper');
   static final Uri DART_INTERCEPTORS =
@@ -1412,6 +1418,7 @@ class JavaScriptBackend extends Backend {
         compiler.enqueuer.codegen.registerStaticUse(getCyclicThrowHelper());
       }
     }
+
     generatedCode[element] = functionCompiler.compile(work);
   }