Add exports needed for glue to build as a component.

webkit/plugins/ppapi/webkit_forwarding_impl.h

 // Copyright (c) 2011 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 "ppapi/shared_impl/webkit_forwarding.h"
 
 #include "base/compiler_specific.h"
+#include "webkit/plugins/webkit_plugins_export.h"
 
 namespace ppapi {
 struct Preferences;
 }
 
 namespace webkit {
 namespace ppapi {
 
 class WebKitForwardingImpl : public ::ppapi::WebKitForwarding {
  public:
-  WebKitForwardingImpl();
-  virtual ~WebKitForwardingImpl();
+  WEBKIT_PLUGINS_EXPORT WebKitForwardingImpl();
+  WEBKIT_PLUGINS_EXPORT virtual ~WebKitForwardingImpl();
 
   virtual void CreateFontForwarding(base::WaitableEvent* event,
                                     const PP_FontDescription_Dev& desc,
                                     const std::string& desc_face,
                                     const ::ppapi::Preferences& prefs,
                                     Font** result) OVERRIDE;
 };
 
 }  // namespace ppapi
 }  // namespace webkit