Handle two cases that we previously weren't expecting....

chrome_frame/chrome_frame_automation.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome_frame/chrome_frame_automation.h"
 
 #include "app/app_switches.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
@@ skipping 61 matching lines @@
 
     // Get AddRef-ed pointer to corresponding TabProxy object
     TabProxy* tab = static_cast<TabProxy*>(tracker_->GetResource(
         message.routing_id()));
     bool handled = false;
     if (tab) {
       handled = tab->OnMessageReceived(message);
       tab->Release();
     } else {
       DLOG(ERROR) << "Failed to find TabProxy for tab:" << message.routing_id();
+      // To prevent subsequent crashes, we set handled to true in this case.
+      handled = true;
     }
     return handled;
   }
 
   virtual void OnChannelError() {
     std::list<AutomationHandle>::const_iterator iter = tabs_list_.begin();
     for (; iter != tabs_list_.end(); ++iter) {
       // Get AddRef-ed pointer to corresponding TabProxy object
       TabProxy* tab = static_cast<TabProxy*>(tracker_->GetResource(*iter));
       if (tab) {
@@ skipping 1366 matching lines @@
     const net::URLRequestStatus& status) {
   automation_server_->Send(new AutomationMsg_RequestEnd(
       tab_->handle(), request_id, status));
 }
 
 void ChromeFrameAutomationClient::OnCookiesRetrieved(bool success,
     const GURL& url, const std::string& cookie_string, int cookie_id) {
   automation_server_->Send(new AutomationMsg_GetCookiesHostResponse(
       tab_->handle(), success, url, cookie_string, cookie_id));
 }