Fixup incorrect include guards.

testing/test_support.h

 // Copyright 2015 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.
 
-#ifndef TESTING_EMBEDDER_TEST_SUPPORT_H_
-#define TESTING_EMBEDDER_TEST_SUPPORT_H_
+#ifndef TESTING_TEST_SUPPORT_H_
+#define TESTING_TEST_SUPPORT_H_
 
 #include <stdlib.h>
 #include <memory>
 #include <string>
 
 #include "public/fpdf_save.h"
 #include "public/fpdfview.h"
 
 #ifdef PDF_ENABLE_V8
 #include "v8/include/v8.h"
@@ skipping 83 matching lines @@
   const std::string& GetString() const { return m_String; }
 
  private:
   static int WriteBlockCallback(FPDF_FILEWRITE* pFileWrite,
                                 const void* data,
                                 unsigned long size);
 
   std::string m_String;
 };
 
-#endif  // TESTING_EMBEDDER_TEST_SUPPORT_H_
+#endif  // TESTING_TEST_SUPPORT_H_