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

content/utility/utility_thread_impl.h

Index: content/utility/utility_thread_impl.h
diff --git a/content/utility/utility_thread_impl.h b/content/utility/utility_thread_impl.h
index 5b186fc21cf0a05e8d1bd3c03f6b4e1b784682f1..4c403425c2ee6d6215470ebace6f7ac95b9bdddd 100644
--- a/content/utility/utility_thread_impl.h
+++ b/content/utility/utility_thread_impl.h
@@ -10,7 +10,7 @@
 
 #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"
 
@@ -21,9 +21,15 @@ 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.
@@ -31,12 +37,7 @@ class UtilityThreadImpl : public UtilityThread,
   ~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();
@@ -63,6 +64,10 @@ class UtilityThreadImpl : public UtilityThread,
   DISALLOW_COPY_AND_ASSIGN(UtilityThreadImpl);
 };
 
+#if defined(COMPILER_MSVC)
+#pragma warning(pop)
+#endif
+
 }  // namespace content
 
 #endif  // CONTENT_UTILITY_UTILITY_THREAD_IMPL_H_