DevTools: Support harmony variable scopes.

Source/bindings/core/v8/DebuggerScript.js

Index: Source/bindings/core/v8/DebuggerScript.js
diff --git a/Source/bindings/core/v8/DebuggerScript.js b/Source/bindings/core/v8/DebuggerScript.js
index ddabaa755389dad0fae6d6919e06cee762bd9bbf..bea3c4570366664d6c51776c1ce5e6ef862af5c1 100644
--- a/Source/bindings/core/v8/DebuggerScript.js
+++ b/Source/bindings/core/v8/DebuggerScript.js
@@ -526,12 +526,18 @@ DebuggerScript._buildScopeObject = function(scopeType, scopeObject)
     case ScopeType.Local:
     case ScopeType.Closure:
     case ScopeType.Catch:
+    case ScopeType.Block:
+    case ScopeType.Script:
         // For transient objects we create a "persistent" copy that contains
         // the same properties.
         // Reset scope object prototype to null so that the proto properties
         // don't appear in the local scope section.
-        result = { __proto__: null };
         var properties = MakeMirror(scopeObject, true /* transient */).properties();
+        // Almost always Script scope will be empty, so just filter out that noise.
+        // Also drop empty Block scopes, should we get any.
+        if (!properties.length && (scopeType === ScopeType.Script || scopeType === ScopeType.Block))
+            break;
+        result = { __proto__: null };
         for (var j = 0; j < properties.length; j++) {
             var name = properties[j].name();
             if (name.charAt(0) === ".")
@@ -543,9 +549,6 @@ DebuggerScript._buildScopeObject = function(scopeType, scopeObject)
     case ScopeType.With:
         result = scopeObject;
         break;
-    case ScopeType.Block:
-        // Unsupported yet. Mustn't be reachable.
-        break;
     }
     return result;
 }