More stubbing out. With this and the rest of Linux pending, test_shell links.

webkit/port/bridge/chromium/PluginsChromium.cpp

Index: webkit/port/bridge/chromium/PluginsChromium.cpp
diff --git a/webkit/port/bridge/chromium/PluginsChromium.cpp b/webkit/port/bridge/chromium/PluginsChromium.cpp
index eb6188d201f36cfb9d25dc70f6297f9105fcb13d..d337bf6aa54ce96b81834e063a206062b23533f5 100644
--- a/webkit/port/bridge/chromium/PluginsChromium.cpp
+++ b/webkit/port/bridge/chromium/PluginsChromium.cpp
@@ -144,11 +144,14 @@ String GetPluginMimeTypeFromExtension(const String& extension) {
     std::string mime_type;
     std::string extension_std = WideToUTF8(
         webkit_glue::StringToStdWString(extension));
+#if !defined(__linux__)
+    // TODO(port): unstub once we have plugin support for Linux
     for (size_t i = 0; i < g_plugins.size(); ++i) {
         if (NPAPI::PluginList::SupportsExtension(
                 g_plugins[i], extension_std, &mime_type))
             break;
     }
+#endif
 
     return webkit_glue::StdStringToString(mime_type);
 }