PrintTo for FilePath -- Pretty-print when comparing FilePaths in gtest

base/file_path.h

Index: base/file_path.h
diff --git a/base/file_path.h b/base/file_path.h
index 3770a8e4c6ef6ee42f86cc670ec9b56db5fb1e4f..09e82693bb24e5974f5ab74bc480c28c6d944b20 100644
--- a/base/file_path.h
+++ b/base/file_path.h
@@ -396,6 +396,9 @@ class BASE_EXPORT FilePath {
   StringType path_;
 };
 
+// This is required by googletest to print a readable output on test failures.
+BASE_EXPORT extern void PrintTo(const FilePath& path, std::ostream* out);
+
 // Macros for string literal initialization of FilePath::CharType[], and for
 // using a FilePath::CharType[] in a printf-style format string.
 #if defined(OS_POSIX)