Make RenderMessageCompletionCallback delete unsent Message

content/browser/renderer_host/render_message_filter.cc

Index: content/browser/renderer_host/render_message_filter.cc
diff --git a/content/browser/renderer_host/render_message_filter.cc b/content/browser/renderer_host/render_message_filter.cc
index 9d8392778e136044efe6c051f04ee55e8bc9bd0a..449afb4d4ea29a453fdb0a6758417dd59337218a 100644
--- a/content/browser/renderer_host/render_message_filter.cc
+++ b/content/browser/renderer_host/render_message_filter.cc
@@ -131,6 +131,12 @@ class RenderMessageCompletionCallback {
   }
 
   virtual ~RenderMessageCompletionCallback() {
+    if (reply_msg_) {
+      // If the owner of this class failed to call SendReplyAndDeleteThis(),
+      // send an error reply to prevent the renderer from being hung.
+      reply_msg_->set_reply_error();
+      filter_->Send(reply_msg_);
+    }
   }
 
   RenderMessageFilter* filter() { return filter_.get(); }
@@ -138,6 +144,7 @@ class RenderMessageCompletionCallback {
 
   void SendReplyAndDeleteThis() {
     filter_->Send(reply_msg_);
+    reply_msg_ = NULL;
     delete this;
   }