Chromium does not throw the exception message by calling NPN_SetException from NPAPI plugin

content/common/npobject_proxy.h

Index: content/common/npobject_proxy.h
===================================================================
--- content/common/npobject_proxy.h	(revision 109161)
+++ content/common/npobject_proxy.h	(working copy)
@@ -95,6 +95,12 @@
 
   virtual IPC::Channel::Listener* GetChannelListener();
 
+  bool HasExceptionThrown() const { return has_exception_thrown_; }
+
+  void SetExceptionThrown(bool has_thrown) {
+    has_exception_thrown_ = has_thrown;
+  }
+
  private:
   NPObjectProxy(NPChannelBase* channel,
                 int route_id,
@@ -104,6 +110,7 @@
   // IPC::Channel::Listener implementation:
   virtual bool OnMessageReceived(const IPC::Message& msg);
   virtual void OnChannelError();
+  virtual void OnSetException(const std::string& msg);
 
   static NPObject* NPAllocate(NPP, NPClass*);
   static void NPDeallocate(NPObject* npObj);
@@ -118,6 +125,10 @@
 
   // The url of the main frame hosting the plugin.
   GURL page_url_;
+
+  // Indicates whether an exception is set via NPN_SetException
+  // called from plugin
+  bool has_exception_thrown_;
 };
 
 #endif  // CONTENT_COMMON_NPOBJECT_PROXY_H_