Let base_unittests build with the components build on android

base/android/path_utils.h

Index: base/android/path_utils.h
diff --git a/base/android/path_utils.h b/base/android/path_utils.h
index 0d95cd38f0d03bcad3ecf5a4794f390447e89290..78f02674ef84814074f945f28e83ec44de2b3d30 100644
--- a/base/android/path_utils.h
+++ b/base/android/path_utils.h
@@ -33,7 +33,7 @@ bool GetDownloadsDirectory(FilePath* result);
 // Retrieves the path to the native JNI libraries via
 // ApplicationInfo.nativeLibraryDir on the Java side. The result is placed in
 // the FilePath pointed to by 'result'.
-bool GetNativeLibraryDirectory(FilePath* result);
+BASE_EXPORT bool GetNativeLibraryDirectory(FilePath* result);
 
 // Retrieves the absolute path to the external storage directory. The result
 // is placed in the FilePath pointed to by 'result'.