Relanding the following revisions....

webkit/glue/webframeloaderclient_impl.cc

Index: webkit/glue/webframeloaderclient_impl.cc
===================================================================
--- webkit/glue/webframeloaderclient_impl.cc	(revision 13602)
+++ webkit/glue/webframeloaderclient_impl.cc	(working copy)
@@ -1447,16 +1447,21 @@
             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