Make V8ValueConverterImpl serialize objects with internal field counts to an

empty object rather than skipping them altogether. This is more consistent with
the expected behaviour of extension APIs.

BUG=330559
R=jochen@chromium.org

Review URL: https://codereview.chromium.org/129153002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243972 0039d316-1c4b-4281-b951-d872f2087c98

chrome/test/data/extensions/api_test/executescript/callback/test.js

@@ -86,9 +86,10 @@ chrome.test.getConfig(function(config) {
         });
       },
 
-      // DOM objects (nodes, properties, etc) should not get converted. We
-      // could try to convert them the best they can but it's undefined what
-      // that means.
+      // DOM objects (nodes, properties, etc) should be converted to empty
+      // objects. We could try to convert them the best they can but it's
+      // undefined what that means. Ideally it'd just throw an exception but
+      // the backwards compatible ship sailed long ago.
       function executeCallbackDOMObjShouldSucceedAndReturnNull() {
         [ 'document',
           'document.getElementById("testDiv")',
@@ -99,7 +100,7 @@ chrome.test.getConfig(function(config) {
           chrome.tabs.executeScript(tabId,
                                     {code: 'var obj = ' + expr + '; obj'},
                                     chrome.test.callbackPass(function(result) {
-            chrome.test.assertEq([null], result, 'Failed for ' + expr);
+            chrome.test.assertEq([{}], result, 'Failed for ' + expr);
           }));
         });
       },

content/renderer/v8_value_converter_impl.cc

@@ -406,8 +406,11 @@ base::Value* V8ValueConverterImpl::FromV8Object(
   //
   // NOTE: check this after |strategy_| so that callers have a chance to
   // do something else, such as convert to the node's name rather than NULL.
+  //
+  // ANOTHER NOTE: returning an empty dictionary here to minimise surprise.
+  // See also http://crbug.com/330559.
   if (val->InternalFieldCount())
-    return NULL;
+    return new base::DictionaryValue();
 
   scoped_ptr<base::DictionaryValue> result(new base::DictionaryValue());
   v8::Handle<v8::Array> property_names(val->GetOwnPropertyNames());