Revert of Move base/prefs to components/prefs

base/prefs/base_prefs_export.h

Index: base/prefs/base_prefs_export.h
diff --git a/base/prefs/base_prefs_export.h b/base/prefs/base_prefs_export.h
index 477e1aa124b858ab500d4487cfaf4c0d8af90047..3d207db890cfe12c66885054186e93b19ec4cf36 100644
--- a/base/prefs/base_prefs_export.h
+++ b/base/prefs/base_prefs_export.h
@@ -2,6 +2,28 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// TODO(brettw) remove this forwarding header when prefs is completely moved to
-// components.
-#include "components/prefs/base_prefs_export.h"
+#ifndef BASE_PREFS_BASE_PREFS_EXPORT_H_
+#define BASE_PREFS_BASE_PREFS_EXPORT_H_
+
+#if defined(COMPONENT_BUILD)
+#if defined(WIN32)
+
+#if defined(BASE_PREFS_IMPLEMENTATION)
+#define BASE_PREFS_EXPORT __declspec(dllexport)
+#else
+#define BASE_PREFS_EXPORT __declspec(dllimport)
+#endif  // defined(BASE_PREFS_IMPLEMENTATION)
+
+#else  // defined(WIN32)
+#if defined(BASE_PREFS_IMPLEMENTATION)
+#define BASE_PREFS_EXPORT __attribute__((visibility("default")))
+#else
+#define BASE_PREFS_EXPORT
+#endif
+#endif
+
+#else  // defined(COMPONENT_BUILD)
+#define BASE_PREFS_EXPORT
+#endif
+
+#endif  // BASE_PREFS_BASE_PREFS_EXPORT_H_