Fix some grammatical errors in base/

base/sys_string_conversions_posix.cc

Index: base/sys_string_conversions_posix.cc
diff --git a/base/sys_string_conversions_posix.cc b/base/sys_string_conversions_posix.cc
index f46259da85f245d464ea2301b97533e20207d05b..17ea896067313cdf7d96531958af0a36ebcadff2 100644
--- a/base/sys_string_conversions_posix.cc
+++ b/base/sys_string_conversions_posix.cc
@@ -79,7 +79,7 @@ std::string SysWideToNativeMB(const std::wstring& wide) {
   memset(&ps, 0, sizeof(ps));
   for (size_t i = 0, j = 0; i < wide.size(); ++i) {
     const wchar_t src = wide[i];
-    // We don't want wcrtomb to do it's funkiness for embedded NULLs.
+    // We don't want wcrtomb to do its funkiness for embedded NULLs.
     size_t res = src ? wcrtomb(&out[j], src, &ps) : 0;
     switch (res) {
       // Handle any errors and return an empty string.