Add exports needed for glue to build as a component.

webkit/plugins/npapi/plugin_lib.h

Index: webkit/plugins/npapi/plugin_lib.h
diff --git a/webkit/plugins/npapi/plugin_lib.h b/webkit/plugins/npapi/plugin_lib.h
index 3ae5d9e6ba203584213e091919a76db5c0ccda2f..9051e2dd820e0b4140a1823d2c0d65b593abe320 100644
--- a/webkit/plugins/npapi/plugin_lib.h
+++ b/webkit/plugins/npapi/plugin_lib.h
@@ -14,6 +14,7 @@
 #include "build/build_config.h"
 #include "webkit/plugins/npapi/plugin_list.h"
 #include "webkit/plugins/npapi/webplugin.h"
+#include "webkit/plugins/webkit_plugins_export.h"
 
 class FilePath;
 
@@ -24,7 +25,7 @@ class PluginInstance;
 
 // A PluginLib is a single NPAPI Plugin Library, and is the lifecycle
 // manager for new PluginInstances.
-class PluginLib : public base::RefCounted<PluginLib> {
+class WEBKIT_PLUGINS_EXPORT PluginLib : public base::RefCounted<PluginLib> {
  public:
   static PluginLib* CreatePluginLib(const FilePath& filename);