Remove support for NPObjects.

content/plugin/plugin_channel.h

Index: content/plugin/plugin_channel.h
diff --git a/content/plugin/plugin_channel.h b/content/plugin/plugin_channel.h
index 1f43f1ef785bbd0fae2f33b219a1467445ea0f90..c022f0dd4bfc453b392ccaa71f1513cad38525ac 100644
--- a/content/plugin/plugin_channel.h
+++ b/content/plugin/plugin_channel.h
@@ -99,10 +99,6 @@ class PluginChannel : public NPChannelBase {
   bool incognito_; // True if the renderer is in incognito mode.
   scoped_refptr<MessageFilter> filter_;  // Handles the modal dialog events.
 
-  // Dummy NPP value used in the plugin process to represent entities other
-  // that other plugin instances for the purpose of object ownership tracking.
-  scoped_ptr<struct _NPP> npp_;
-
   DISALLOW_COPY_AND_ASSIGN(PluginChannel);
 };