If CreateDirectory() fails during extension unpacking, log the exact OS call that failed.

base/file_util.h

Index: base/file_util.h
diff --git a/base/file_util.h b/base/file_util.h
index b2e176bda5e98dfefacf65414c1fb4589d89da39..a16c5c72bc3b7fb2d666c6febece2d4bacd67240 100644
--- a/base/file_util.h
+++ b/base/file_util.h
@@ -281,6 +281,14 @@ bool CreateNewTempDirectory(const FilePath::StringType& prefix,
 // already exists.  The directory is only readable by the current user.
 bool CreateDirectory(const FilePath& full_path);
 
+#if defined(OS_WIN)
+// Added for debugging an issue where CreateDirectory() fails.  LOG(*) does
+// not work, because the failure happens in a sandboxed process.
+// TODO(skerner): Remove once crbug/35198 is resolved.
+bool CreateDirectoryExtraLogging(const FilePath& full_path,
+                                 std::ostream& error);
+#endif  // defined (OS_WIN)
+
 // Returns the file size. Returns true on success.
 bool GetFileSize(const FilePath& file_path, int64* file_size);