npapi plugins: Make sure WebPlugin has no key functions on mac.

webkit/plugins/npapi/webplugin.cc

 // 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 "webkit/plugins/npapi/webplugin.h"
 
 namespace webkit {
 namespace npapi {
 
 WebPluginGeometry::WebPluginGeometry()
     : window(gfx::kNullPluginWindow),
       rects_valid(false),
       visible(false) {
 }
 
 WebPluginGeometry::~WebPluginGeometry() {
 }
 
 bool WebPluginGeometry::Equals(const WebPluginGeometry& rhs) const {
   return window == rhs.window &&
          window_rect == rhs.window_rect &&
          clip_rect == rhs.clip_rect &&
          cutout_rects == rhs.cutout_rects &&
          rects_valid == rhs.rects_valid &&
          visible == rhs.visible;
 }
 
-#if defined(OS_MACOSX)
-WebPluginAcceleratedSurface* WebPlugin::GetAcceleratedSurface(
-    gfx::GpuPreference gpu_preference) {
-  return NULL;
-}
-#endif
-
 }  // namespace npapi
 }  // namespace webkit