Unify the three places that patch font loading for PDFium on Windows.

content/utility/utility_thread_impl.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_UTILITY_UTILITY_THREAD_IMPL_H_
 #define CONTENT_UTILITY_UTILITY_THREAD_IMPL_H_
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
-#include "content/child/child_thread.h"
+#include "content/child/child_thread_impl.h"
 #include "content/common/content_export.h"
 #include "content/public/utility/utility_thread.h"
 
 namespace base {
 class FilePath;
 }
 
 namespace content {
 class BlinkPlatformImpl;
 
+#if defined(COMPILER_MSVC)
+// See explanation for other RenderViewHostImpl which is the same issue.
+#pragma warning(push)
+#pragma warning(disable: 4250)
+#endif
+
 // This class represents the background thread where the utility task runs.
 class UtilityThreadImpl : public UtilityThread,
-                          public ChildThread {
+                          public ChildThreadImpl {
  public:
   UtilityThreadImpl();
   // Constructor that's used when running in single process mode.
   explicit UtilityThreadImpl(const std::string& channel_name);
   ~UtilityThreadImpl() override;
   void Shutdown() override;
 
-  bool Send(IPC::Message* msg) override;
   void ReleaseProcessIfNeeded() override;
-#if defined(OS_WIN)
-  virtual void PreCacheFont(const LOGFONT& log_font) override;
-  virtual void ReleaseCachedFonts() override;
-#endif
 
  private:
   void Init();
 
   // ChildThread implementation.
   bool OnControlMessageReceived(const IPC::Message& msg) override;
 
   // IPC message handlers.
   void OnBatchModeStarted();
   void OnBatchModeFinished();
 
 #if defined(OS_POSIX) && defined(ENABLE_PLUGINS)
   void OnLoadPlugins(const std::vector<base::FilePath>& plugin_paths);
 #endif
 
   // True when we're running in batch mode.
   bool batch_mode_;
 
   // True if running in single process mode.
   bool single_process_;
 
   scoped_ptr<BlinkPlatformImpl> blink_platform_impl_;
 
   DISALLOW_COPY_AND_ASSIGN(UtilityThreadImpl);
 };
 
+#if defined(COMPILER_MSVC)
+#pragma warning(pop)
+#endif
+
 }  // namespace content
 
 #endif  // CONTENT_UTILITY_UTILITY_THREAD_IMPL_H_