content: Cleanup class/struct forward declarations

content/renderer/pepper/host_var_tracker.h

 // Copyright (c) 2012 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 CONTENT_RENDERER_PEPPER_HOST_VAR_TRACKER_H_
 #define CONTENT_RENDERER_PEPPER_HOST_VAR_TRACKER_H_
 
 #include <stdint.h>
 
 #include <map>
 
 #include "base/compiler_specific.h"
 #include "base/containers/hash_tables.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "content/common/content_export.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/shared_impl/host_resource.h"
 #include "ppapi/shared_impl/resource_tracker.h"
 #include "ppapi/shared_impl/var_tracker.h"
 #include "v8/include/v8.h"
 
 namespace ppapi {
 class ArrayBufferVar;
 class V8ObjectVar;
-class Var;
 }
 
 namespace content {
 
 class HostVarTracker : public ppapi::VarTracker {
  public:
   HostVarTracker();
   ~HostVarTracker() override;
 
   // Tracks all live V8ObjectVar. This is so we can map between instance +
@@ skipping 67 matching lines @@
   typedef std::map<int, SharedMemoryMapEntry> SharedMemoryMap;
   SharedMemoryMap shared_memory_map_;
   uint32_t last_shared_memory_map_id_;
 
   DISALLOW_COPY_AND_ASSIGN(HostVarTracker);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PEPPER_HOST_VAR_TRACKER_H_