Cleanup: Remove unneeded forward declarations in webkit/plugins/.

webkit/plugins/npapi/plugin_list.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.
 
 #ifndef WEBKIT_PLUGINS_NPAPI_PLUGIN_LIST_H_
 #define WEBKIT_PLUGINS_NPAPI_PLUGIN_LIST_H_
 
 #include <set>
 #include <string>
 #include <utility>
@@ skipping 16 matching lines @@
 template <typename T>
 struct DefaultLazyInstanceTraits;
 
 }  // namespace base
 
 namespace webkit {
 namespace npapi {
 
 extern FilePath::CharType kDefaultPluginLibraryName[];
 
-class PluginInstance;
-
 // This struct holds entry points into a plugin.  The entry points are
 // slightly different between Win/Mac and Unixes.  Note that the interface for
 // querying plugins is synchronous and it is preferable to use a higher-level
 // asynchronous information to query information.
 struct PluginEntryPoints {
 #if !defined(OS_POSIX) || defined(OS_MACOSX)
   NP_GetEntryPointsFunc np_getentrypoints;
 #endif
   NP_InitializeFunc np_initialize;
   NP_ShutdownFunc np_shutdown;
@@ skipping 249 matching lines @@
   // Set to true if the default plugin is enabled.
   bool default_plugin_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(PluginList);
 };
 
 }  // namespace npapi
 }  // namespace webkit
 
 #endif  // WEBKIT_PLUGINS_NPAPI_PLUGIN_LIST_H_