Add a .clang-format file to give us local control over Chromium style.

Based on the. `clang-format` from chromium project
https://chromium.googlesource.com/chromium/src/+/HEAD/.clang-format

Change-Id: I9df4f5c917521b02b0cdc911f15c12102758f7e1
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/2384071
Reviewed-by: Mark Mentovai <mark@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/.clang-format b/.clang-format
new file mode 100644
index 0000000..d175ab7
--- /dev/null
+++ b/.clang-format
@@ -0,0 +1,9 @@
+# Defines the Chromium style for automatic reformatting.
+# https://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