diff --git a/.clang-format b/.clang-format
index 2fb833a..30ed2de 100644
--- a/.clang-format
+++ b/.clang-format
@@ -1,2 +1,12 @@
+# Defines the Chromium style for automatic reformatting.
 # http://clang.llvm.org/docs/ClangFormatStyleOptions.html
 BasedOnStyle: Chromium
+# This defaults to 'Auto'. Explicitly set it for a while, so that
+# 'vector<vector<int> >' in existing files gets formatted to
+# 'vector<vector<int>>'. ('Auto' means that clang-format will only use
+# 'int>>' if the file already contains at least one such instance.)
+Standard: Cpp11
+
+# TODO(crbug.com/1392808): Remove when InsertBraces has been upstreamed into
+# the Chromium style (is implied by BasedOnStyle: Chromium).
+InsertBraces: true