Re-add source files to gyp config for gcapi_dll. Removing them seems to make VS2005 unhappy.

chrome/installer/gcapi/gcapi_reactivation.h

Index: chrome/installer/gcapi/gcapi_reactivation.h
diff --git a/chrome/installer/gcapi/gcapi_reactivation.h b/chrome/installer/gcapi/gcapi_reactivation.h
new file mode 100644
index 0000000000000000000000000000000000000000..5ace0b82ccbf9af1e14a5ef72289d02299bceafa
--- /dev/null
+++ b/chrome/installer/gcapi/gcapi_reactivation.h
@@ -0,0 +1,19 @@
+// 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 CHROME_INSTALLER_GCAPI_GCAPI_REACTIVATION_H_
+#define CHROME_INSTALLER_GCAPI_GCAPI_REACTIVATION_H_
+#pragma once
+
+#include <windows.h>
+
+#include <string>
+#include <vector>
+
+bool HasBeenReactivatedByBrandCodes(
+    const std::vector<std::wstring>& brand_codes);
+
+bool SetReactivationBrandCode(const std::wstring& brand_code);
+
+#endif  // CHROME_INSTALLER_GCAPI_GCAPI_REACTIVATION_H_