Revert of Revert of Add clang-format binaries and scripts for all platforms

third_party/clang_format/README.txt

+This folder contains clang-format binaries. The binaries will be automatically
+downloaded from Google Storage by gclient runhooks for the current platform.
+
+For a walkthrough on how to maintain these binaries:
+  https://code.google.com/p/chromium/wiki/UpdatingClangFormatBinaries
+
+To upload a file:
+  python ~/depot_tools/upload_to_google_storage.py -b chromium-clang-format <FILENAME>
+
+To download a file given a .sha1 file:
+  python ~/depot_tools/download_from_google_storage.py -b chromium-clang-format -s <FILENAME>.sha1
+
+List the contents of GN's Google Storage bucket:
+  python ~/depot_tools/third_party/gsutil/gsutil ls gs://chromium-clang-format/
+
+To initialize gsutil's credentials:
+  python ~/depot_tools/third_party/gsutil/gsutil config
+
+  That will give a URL which you should log into with your web browser. The
+  username should be the one that is on the ACL for the "chromium-clang-format"
+  bucket (probably your @google.com address). Contact the build team for help
+  getting access if necessary.
+
+  Copy the code back to the command line util. Ignore the project ID (it's OK
+  to just leave blank when prompted).
+
+gsutil documentation:
+  https://developers.google.com/storage/docs/gsutil