Fix ALL the include guards.

core/include/fpdfapi/fpdf_module.h

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
  
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
-#ifndef _FPDF_MODULE_
-#define _FPDF_MODULE_
-#ifndef _FXCRT_EXTENSION_
+#ifndef CORE_INCLUDE_FPDFAPI_FPDF_MODULE_H_
+#define CORE_INCLUDE_FPDFAPI_FPDF_MODULE_H_
+
 #include "../fxcrt/fx_ext.h"
-#endif
+
 class CPDF_ModuleMgr;
 class CPDF_PageModuleDef;
 class CPDF_RenderModuleDef;
 class CPDF_SecurityHandler;
 class CCodec_ModuleMgr;
 class CPDF_Dictionary;
 class ICodec_JpegModule;
 class ICodec_JpxModule;
 class ICodec_FaxModule;
 class ICodec_Jbig2Module;
@@ skipping 164 matching lines @@
 
     virtual void        DestroyPageCache(CPDF_PageRenderCache*) {}
 
     virtual void        NotifyDecoderAvailable() {}
 
     virtual CPDF_RenderConfig* GetConfig()
     {
         return NULL;
     }
 };
-#endif
+
+#endif  // CORE_INCLUDE_FPDFAPI_FPDF_MODULE_H_