Block NPAPI plug-ins in Metro mode instead of not loading them at all.

chrome/common/render_messages.h

Index: chrome/common/render_messages.h
diff --git a/chrome/common/render_messages.h b/chrome/common/render_messages.h
index e47720e1dc8a1de7f4f215331fac2347cc0a7428..25b0227db6bd86fad4739be118cce1279c8db16a 100644
--- a/chrome/common/render_messages.h
+++ b/chrome/common/render_messages.h
@@ -59,6 +59,7 @@ struct ChromeViewHostMsg_GetPluginInfo_Status {
     kClickToPlay,
     kDisabled,
     kNotFound,
+    kNPAPINotSupported,
     kOutdatedBlocked,
     kOutdatedDisallowed,
     kUnauthorized,
@@ -483,6 +484,10 @@ IPC_MESSAGE_ROUTED0(ChromeViewHostMsg_OpenAboutPlugins)
 IPC_MESSAGE_ROUTED1(ChromeViewHostMsg_CouldNotLoadPlugin,
                     FilePath /* plugin_path */)
 
+// Tells the browser that we blocked a plug-in because NPAPI is not supported.
+IPC_MESSAGE_ROUTED1(ChromeViewHostMsg_NPAPINotSupported,
+                    std::string /* identifer */)
+
 // Send a snapshot of the tab contents to the render host.
 IPC_MESSAGE_ROUTED1(ChromeViewHostMsg_Snapshot,
                     SkBitmap /* bitmap */)