Merge third_party/brotli/src from https://chromium.googlesource.com/external/font-compression-reference.git at 0829e37293abc2523a1d2b0f4d68ff7b5fcd8e01

This commit was generated by merge_from_chromium.py.

Change-Id: I0395c498efb0ff33f9dbe66d15209b4780080163