Fix some webview plugin attach-ment code.

content/renderer/browser_plugin/browser_plugin_bindings.cc

Index: content/renderer/browser_plugin/browser_plugin_bindings.cc
diff --git a/content/renderer/browser_plugin/browser_plugin_bindings.cc b/content/renderer/browser_plugin/browser_plugin_bindings.cc
index e78248fc513e4c826621950b38c3e871cce31f9d..624e19f88e5f65047960943516d472f3ece0ade7 100644
--- a/content/renderer/browser_plugin/browser_plugin_bindings.cc
+++ b/content/renderer/browser_plugin/browser_plugin_bindings.cc
@@ -236,6 +236,13 @@ class BrowserPluginBindingAttach: public BrowserPluginMethodBinding {
   virtual bool Invoke(BrowserPluginBindings* bindings,
                       const NPVariant* args,
                       NPVariant* result) OVERRIDE {
+    bool attached = InvokeHelper(bindings, args);
+    BOOLEAN_TO_NPVARIANT(attached, *result);
+    return true;
+  }
+
+ private:
+  bool InvokeHelper(BrowserPluginBindings* bindings, const NPVariant* args) {
     if (!bindings->instance()->render_view())
       return false;
 
@@ -259,8 +266,6 @@ class BrowserPluginBindingAttach: public BrowserPluginMethodBinding {
     bindings->instance()->Attach(instance_id, extra_params.Pass());
     return true;
   }
-
- private:
   DISALLOW_COPY_AND_ASSIGN(BrowserPluginBindingAttach);
 };