Pure pedantry: Replace all ".size() == 0" with ".empty()".

base/file_util_posix.cc

Index: base/file_util_posix.cc
diff --git a/base/file_util_posix.cc b/base/file_util_posix.cc
index 7e4c3a9709d37236265e827f3f3533ff19b4ceb0..8df0d27f2dfbde297b8bc9025f3ce13800d4a531 100644
--- a/base/file_util_posix.cc
+++ b/base/file_util_posix.cc
@@ -633,7 +633,7 @@ FileEnumerator::FileEnumerator(const FilePath& root_path,
   // The Windows version of this code appends the pattern to the root_path,
   // potentially only matching against items in the top-most directory.
   // Do the same here.
-  if (pattern.size() == 0)
+  if (pattern.empty())
     pattern_ = FilePath::StringType();
   pending_paths_.push(root_path);
 }