Backed out 2 changesets (bug 1776104) as requested by Andi

Backed out changeset c2f124ed65ec (bug 1776104)
Backed out changeset 05da7d6fa999 (bug 1776104)

.clang-format-ignore

@@ -7,6 +7,12 @@ config/msvc-stl-wrapper.template.h
 intl/components/src/LocaleGenerated.cpp
 js/src/builtin/intl/TimeZoneDataGenerated.h
 
+# Don't want to reformat irregexp (third-party code)
+js/src/irregexp/imported/.*
+
+# Don't want to reformat zydis (third-party library subject to occasional updates).
+js/src/zydis/.*
+
 # Generated by js/src/util/make_unicode.py
 js/src/util/Unicode.cpp
 js/src/util/UnicodeNonBMP.h
@@ -15,6 +21,7 @@ js/src/util/UnicodeNonBMP.h
 layout/style/nsCSSAnonBoxList.h
 layout/style/nsCSSCounterDescList.h
 layout/style/nsCSSFontDescList.h
+layout/style/nsCSSKeywordList.h
 layout/style/nsCSSPseudoElementList.h
 layout/style/nsCSSVisitedDependentPropList.h
 layout/style/nsDOMCSSValueList.h
@@ -58,66 +65,45 @@ xpcom/reflect/xptcall/md/unix/.*
 
 # Generated from ./tools/rewriting/ThirdPartyPaths.txt
 # awk '{print ""$1".*"}' ./tools/rewriting/ThirdPartyPaths.txt
-browser/components/newtab/vendor/.*
-browser/components/pocket/content/panels/js/vendor/.*
 browser/components/translation/cld2/.*
-browser/extensions/formautofill/content/third-party/.*
-browser/extensions/formautofill/test/fixtures/third_party/.*
-devtools/client/inspector/markup/test/lib_.*
-devtools/client/jsonview/lib/require.js
-devtools/client/shared/build/babel.js
-devtools/client/shared/source-map/.*
+browser/extensions/mortar/ppapi/.*
 devtools/client/shared/sourceeditor/codemirror/.*
-devtools/client/shared/sourceeditor/test/cm_mode_ruby.js
-devtools/client/shared/sourceeditor/test/codemirror/.*
-devtools/client/shared/vendor/.*
-devtools/shared/jsbeautify/.*
-devtools/shared/node-properties/.*
-devtools/shared/qrcode/decoder/.*
-devtools/shared/qrcode/encoder/.*
-devtools/shared/sprintfjs/.*
-devtools/shared/storage/vendor/.*
-dom/canvas/test/webgl-conf/checkout/.*
-dom/imptests/.*
+dom/canvas/test/webgl-conf/checkout/closure-library/.*
 dom/media/gmp/rlz/.*
+dom/media/gmp/widevine-adapter/content_decryption_module.h
 dom/media/gmp/widevine-adapter/content_decryption_module_export.h
 dom/media/gmp/widevine-adapter/content_decryption_module_ext.h
 dom/media/gmp/widevine-adapter/content_decryption_module_proxy.h
-dom/media/gmp/widevine-adapter/content_decryption_module.h
 dom/media/platforms/ffmpeg/ffmpeg57/.*
 dom/media/platforms/ffmpeg/ffmpeg58/.*
-dom/media/platforms/ffmpeg/ffmpeg59/.*
 dom/media/platforms/ffmpeg/libav53/.*
 dom/media/platforms/ffmpeg/libav54/.*
 dom/media/platforms/ffmpeg/libav55/.*
-dom/media/webaudio/test/blink/.*
 dom/media/webrtc/transport/third_party/.*
 dom/media/webspeech/recognition/endpointer.cc
 dom/media/webspeech/recognition/endpointer.h
-dom/media/webspeech/recognition/energy_endpointer_params.cc
-dom/media/webspeech/recognition/energy_endpointer_params.h
 dom/media/webspeech/recognition/energy_endpointer.cc
 dom/media/webspeech/recognition/energy_endpointer.h
-dom/media/webvtt/vtt.jsm
-dom/tests/mochitest/ajax/.*
-dom/tests/mochitest/dom-level1-core/.*
-dom/tests/mochitest/dom-level2-core/.*
-dom/tests/mochitest/dom-level2-html/.*
-dom/u2f/tests/pkijs/.*
+dom/media/webspeech/recognition/energy_endpointer_params.cc
+dom/media/webspeech/recognition/energy_endpointer_params.h
 dom/webauthn/cbor-cpp/.*
-dom/webauthn/tests/pkijs/.*
+dom/webauthn/winwebauthn/webauthn.h
 editor/libeditor/tests/browserscope/lib/richtext/.*
 editor/libeditor/tests/browserscope/lib/richtext2/.*
 extensions/spellcheck/hunspell/src/.*
-gfx/angle/checkout/.*
+gfx/angle/.*
 gfx/cairo/.*
 gfx/graphite2/.*
 gfx/harfbuzz/.*
-gfx/ots/.*
+gfx/ots/src/.*
+gfx/ots/include/.*
+gfx/ots/tests/.*
 gfx/qcms/.*
+gfx/sfntly/.*
 gfx/skia/.*
 gfx/vr/service/openvr/.*
 gfx/vr/service/openvr/headers/openvr.h
+gfx/vr/service/openvr/src/README
 gfx/vr/service/openvr/src/dirtools_public.cpp
 gfx/vr/service/openvr/src/dirtools_public.h
 gfx/vr/service/openvr/src/envvartools_public.cpp
@@ -128,34 +114,29 @@ gfx/vr/service/openvr/src/ivrclientcore.h
 gfx/vr/service/openvr/src/openvr_api_public.cpp
 gfx/vr/service/openvr/src/pathtools_public.cpp
 gfx/vr/service/openvr/src/pathtools_public.h
-gfx/vr/service/openvr/src/README
 gfx/vr/service/openvr/src/sharedlibtools_public.cpp
 gfx/vr/service/openvr/src/sharedlibtools_public.h
 gfx/vr/service/openvr/src/strtools_public.cpp
 gfx/vr/service/openvr/src/strtools_public.h
 gfx/vr/service/openvr/src/vrpathregistry_public.cpp
 gfx/vr/service/openvr/src/vrpathregistry_public.h
-gfx/wr/.*
 gfx/ycbcr/.*
+intl/hyphenation/hyphen/.*
 intl/icu/.*
 ipc/chromium/src/third_party/.*
 js/src/ctypes/libffi/.*
-js/src/dtoa.c
+js/src/dtoa.c.*
 js/src/editline/.*
-js/src/irregexp/imported/.*
 js/src/jit/arm64/vixl/.*
-js/src/octane/.*
 js/src/vtune/disable_warnings.h
+js/src/vtune/ittnotify.h
 js/src/vtune/ittnotify_config.h
 js/src/vtune/ittnotify_static.c
 js/src/vtune/ittnotify_static.h
 js/src/vtune/ittnotify_types.h
-js/src/vtune/ittnotify.h
 js/src/vtune/jitprofiling.c
 js/src/vtune/jitprofiling.h
 js/src/vtune/legacy/.*
-js/src/zydis/.*
-layout/docs/css-gap-decorations/.*
 media/ffvpx/.*
 media/kiss_fft/.*
 media/libaom/.*
@@ -175,57 +156,52 @@ media/libvorbis/.*
 media/libvpx/.*
 media/libwebp/.*
 media/libyuv/.*
-media/mozva/va.*
-media/mp4parse-rust/.*
+media/mozva/va/.*
 media/openmax_dl/.*
 media/openmax_il/.*
-media/webrtc/signaling/gtest/MockCall.h
+media/webrtc/signaling/src/sdp/sipcc/.*
+media/webrtc/trunk/.*
 mfbt/double-conversion/double-conversion/.*
 mfbt/lz4/.*
+mobile/android/geckoview/src/thirdparty/.*
 modules/brotli/.*
 modules/fdlibm/.*
 modules/freetype2/.*
-modules/woff2/.*
+modules/libbz2/.*
+modules/pdfium/.*
+modules/woff2/include/.*
+modules/woff2/src/.*
 modules/xz-embedded/.*
 modules/zlib/.*
 mozglue/misc/decimal/.*
 mozglue/tests/glibc_printf_tests/.*
 netwerk/dns/nsIDNKitInterface.h
 netwerk/sctp/src/.*
+netwerk/srtp/src/.*
 nsprpub/.*
 other-licenses/.*
 parser/expat/.*
-remote/cdp/test/browser/chrome-remote-interface.js
-remote/test/puppeteer/.*
 security/nss/.*
-security/sandbox/chromium-shim/.*
 security/sandbox/chromium/.*
-testing/mochitest/MochiKit/.*
-testing/mochitest/pywebsocket3/.*
-testing/mochitest/tests/MochiKit-1.4.2/.*
-testing/modules/sinon-7.2.7.js
-testing/mozbase/mozproxy/mozproxy/backends/mitm/scripts/catapult/.*
+security/sandbox/chromium-shim/.*
+testing/gtest/gmock/.*
+testing/gtest/gtest/.*
 testing/talos/talos/tests/dromaeo/.*
 testing/talos/talos/tests/kraken/.*
 testing/talos/talos/tests/v8_7/.*
 testing/web-platform/tests/resources/webidl2/.*
 testing/web-platform/tests/tools/third_party/.*
-testing/xpcshell/dns-packet/.*
-testing/xpcshell/node-http2/.*
-testing/xpcshell/node-ip/.*
-testing/xpcshell/odoh-wasm/.*
 third_party/.*
-toolkit/components/certviewer/content/vendor/.*
 toolkit/components/jsoncpp/.*
-toolkit/components/normandy/vendor/.*
-toolkit/components/passwordmgr/PasswordRulesParser.jsm
 toolkit/components/protobuf/.*
 toolkit/components/url-classifier/chromium/.*
-toolkit/components/utils/mozjexl.js
+toolkit/components/url-classifier/protobuf/.*
 toolkit/crashreporter/breakpad-client/.*
 toolkit/crashreporter/google-breakpad/.*
 tools/fuzzing/libfuzzer/.*
 tools/profiler/core/vtune/.*
+# tools/profiler/public/GeckoTraceEvent.h is a modified vendored copy
+tools/profiler/public/GeckoTraceEvent.h
 xpcom/build/mach_override.c
 xpcom/build/mach_override.h
 xpcom/io/crc32c.c