Relanding the following revisions....

webkit/glue/webframeloaderclient_impl.cc

 // Copyright (c) 2006-2008 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 "config.h"
 #include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 
@@ skipping 1429 matching lines @@
     for (unsigned int i = 0; i < param_names.size(); i++) {
       String lowercase_param_name = param_names[i].lower();
       if (lowercase_param_name == "classid") {
         activex_shim::GetClsidFromClassidAttribute(
             webkit_glue::CStringToStdString(param_values[i].latin1()), &clsid);
       } else if (lowercase_param_name == "codebase") {
         version = activex_shim::GetVersionFromCodebaseAttribute(
             webkit_glue::CStringToStdString(param_values[i].latin1()));
       }
     }
-    // We only allowed specific ActiveX controls to run from certain websites.
-    if (!activex_shim::IsActiveXAllowed(clsid, url))
-      return NULL;
-    // We need to pass the combined clsid + version to PluginsList, so that it
-    // would detect if the requested version is installed. If not, it needs
-    // to use the default plugin to update the control.
-    if (!version.empty())
-      combined_clsid = clsid + "#" + version;
-    else
-      combined_clsid = clsid;
+
+    // Attempt to map this clsid to a known NPAPI mime type if possible, failing
+    // which we attempt to load the activex shim for the clsid.
+    if (!activex_shim::GetMimeTypeForClsid(clsid, &my_mime_type)) {
+      // We only allowed specific ActiveX controls to run from certain websites.
+      if (!activex_shim::IsActiveXAllowed(clsid, url))
+        return NULL;
+      // We need to pass the combined clsid + version to PluginsList, so that it
+      // would detect if the requested version is installed. If not, it needs
+      // to use the default plugin to update the control.
+      if (!version.empty())
+        combined_clsid = clsid + "#" + version;
+      else
+        combined_clsid = clsid;
+    }
   }
 #endif
 
   std::string actual_mime_type;
   WebPluginDelegate* plugin_delegate =
       d->CreatePluginDelegate(webframe_->webview_impl(), gurl, my_mime_type,
                               combined_clsid, &actual_mime_type);
   if (!plugin_delegate)
     return NULL;
 
@@ skipping 132 matching lines @@
   if (!web_view) {
     return NULL;
   }
   WebDevToolsAgentImpl* tools_agent = web_view->GetWebDevToolsAgentImpl();
   if (tools_agent) {
     return tools_agent->net_agent_impl();
   } else {
     return NULL;
   }
 }