third_party/protobuf: Update to cf242503

Followed steps on README.chromium to update protobuf. Added
BUILD.gn.template and gen_extra_chromium_files to automated
generation of extra files and BUILD.gn file.

removed unnecesary patches, updated patches and added new patch for
a missing override

Bug: 874265
Change-Id: Icfc221ef47dab7191403c73791509b79383ac6b7
Reviewed-on: https://chromium-review.googlesource.com/1081411
Commit-Queue: Andres Medina <[email protected]>
Reviewed-by: Scott Violet <[email protected]>
Reviewed-by: Mathieu Perreault <[email protected]>
Reviewed-by: Yuwei Huang <[email protected]>
Reviewed-by: Xiangjun Zhang <[email protected]>
Reviewed-by: Tommy Nyquist <[email protected]>
Reviewed-by: Peter Kasting <[email protected]>
Cr-Commit-Position: refs/heads/master@{#586339}
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index 2d49c87..2c0898b 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -1935,6 +1935,7 @@
   # matching the above patterns, which trigger false positives.
   exclude_paths = [
       'third_party/crashpad/*',
+      'third_party/protobuf/benchmarks/python/*',
       'third_party/third_party/blink/renderer/platform/bindings/*',
       'third_party/win_build_output/*',
   ]