Merging upstream version 126.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

2 files changed, 78 insertions, 6 deletions

diff --git a/third_party/libwebrtc/docs/native-code/development/README.md b/third_party/libwebrtc/docs/native-code/development/README.md
index 8a2678e6cf..02d148c7d7 100644
--- a/third_party/libwebrtc/docs/native-code/development/README.md
+++ b/third_party/libwebrtc/docs/native-code/development/README.md
@@ -98,11 +98,7 @@ configuration untouched (stored in the args.gn file), do:
 $ gn clean out/Default
 ```
 
-To build the fuzzers residing in the [test/fuzzers][fuzzers] directory, use
-```
-$ gn gen out/fuzzers --args='use_libfuzzer=true optimize_for_fuzzing=true'
-```
-Depending on the fuzzer additional arguments like `is_asan`, `is_msan` or `is_ubsan_security` might be required.
+To build the fuzzers residing in the [test/fuzzers][fuzzers-dir] directory, read the instructions at the [fuzzers][fuzzers] page.
 
 See the [GN][gn-doc] documentation for all available options. There are also more
 platform specific tips on the [Android][webrtc-android-development] and
@@ -129,6 +125,11 @@ $ autoninja all -C out/Default
 
 See [Ninja build rules][ninja-build-rules] to read more about difference between `ninja` and `ninja all`.
 
+To build a particular target (like a fuzzer which is not included in the main target) use
+
+```
+autoninja -C out/Default h264_depacketizer_fuzzer
+```
 
 ## Using Another Build System
 
@@ -288,4 +289,5 @@ Target name `turnserver`. Used for unit tests.
 [rfc-5766]: https://tools.ietf.org/html/rfc5766
 [m80-log]: https://webrtc.googlesource.com/src/+log/branch-heads/3987
 [m80]: https://webrtc.googlesource.com/src/+/branch-heads/3987
-[fuzzers]: https://webrtc.googlesource.com/src/+/main/test/fuzzers/
+[fuzzers-dir]: https://webrtc.googlesource.com/src/+/main/test/fuzzers/
+[fuzzers]: https://webrtc.googlesource.com/src/+/main/docs/native-code/development/fuzzers/
diff --git a/third_party/libwebrtc/docs/native-code/development/fuzzers/README.md b/third_party/libwebrtc/docs/native-code/development/fuzzers/README.md
new file mode 100644
index 0000000000..cac77cdc07
--- /dev/null
+++ b/third_party/libwebrtc/docs/native-code/development/fuzzers/README.md
@@ -0,0 +1,70 @@
+# Fuzzing in WebRTC
+
+## Intro
+WebRTC currently uses libfuzzer for fuzz testing however FuzzTest is a new approach which we have not yet looked into but we will in the future.
+
+Before continuing, read the [libfuzzer][libfuzzer-getting-started] and [FuzzTest][fuzztest-getting-started] getting started docs to get familar.
+
+## Compiling locally
+To build the fuzzers residing in the [test/fuzzers][fuzzers] directory, use
+```
+$ gn gen out/fuzzers --args='use_libfuzzer=true optimize_for_fuzzing=true'
+```
+Depending on the fuzzer additional arguments like `is_asan`, `is_msan` or `is_ubsan_security` might be required.
+
+See the [GN][gn-doc] documentation for all available options. There are also more
+platform specific tips on the [Android][webrtc-android-development] and
+[iOS][webrtc-ios-development] instructions.
+
+## Add new fuzzers
+Create a new `.cc` file in the [test/fuzzers][fuzzers] directory, use existing files as a guide.
+
+Add a new `webrtc_fuzzers_test` build rule in the [test/fuzzers/BUILD.gn][BUILD.gn], use existing rules as a guide.
+
+Ensure it compiles and executes locally then add it to a gerrit CL and upload it for review, e.g.
+
+```
+$ autoninja -C out/fuzzers test/fuzzers:h264_depacketizer_fuzzer
+```
+
+It can then be executed like so:
+```
+$ out/fuzzers/bin/run_h264_depacketizer_fuzzer
+```
+
+## Running fuzzers automatically
+All fuzzer tests in the [test/fuzzers/BUILD.gn][BUILD.gn] file are compiled per CL on the [libfuzzer bot][libfuzzer-bot].
+This is only to verify that it compiles, this bot does not do any fuzz testing.
+
+When WebRTC is [rolled][webrtc-autoroller] into to Chromium, the libfuzz bots in the [chromium.fuzz][chromium-fuzz] will compile it, zip it and then upload to https://clusterfuzz.com for execution.
+
+You can verify that the fuzz test is being executed by:
+ - Navigate to a bot in the [chromium.fuzz][chromium-fuzz] libfuzzer waterfall, e.g. [ Libfuzzer Upload Linux ASan bot/linux bot][linux-bot].
+ - Click on the latest `build#` link.
+ - Search for `//third_party/webrtc/test/fuzzers` in the `raw_io.output_text_refs_` file in the `calculate_all_fuzzers` step.
+ - Verify that the new fuzzer (as it's named in the `webrtc_fuzzers_test` build rule) is present.
+ - Also verify that it's _NOT_ in the `no_clusterfuzz` file in the `calculate_no_clusterfuzz` step. If it is, file a bug at https://bugs.webrtc.org.
+
+Bugs are filed automatically in https://crbug.com in the blink > WebRTC component and assigned based on [test/fuzzers/OWNERS][OWNERS] file or the commit history.
+
+If you are a non-googler, you can only view data from https://clusterfuzz.com if your account is CC'ed on the reported bug.
+
+## Additional reading
+
+[Libfuzzer in Chromium][libfuzzer-chromium]
+
+
+[libfuzzer-chromium]: https://chromium.googlesource.com/chromium/src/+/HEAD/testing/libfuzzer/README.md
+[libfuzzer-bot]: https://ci.chromium.org/ui/p/webrtc/builders/luci.webrtc.ci/Linux64%20Release%20%28Libfuzzer%29
+[fuzzers]: https://webrtc.googlesource.com/src/+/main/test/fuzzers/
+[OWNERS]: https://webrtc.googlesource.com/src/+/main/test/fuzzers/OWNERS
+[BUILD.gn]: https://webrtc.googlesource.com/src/+/main/test/fuzzers/BUILD.gn
+[gn]: https://gn.googlesource.com/gn/+/main/README.md
+[gn-doc]: https://gn.googlesource.com/gn/+/main/docs/reference.md#IDE-options
+[webrtc-android-development]: https://webrtc.googlesource.com/src/+/main/docs/native-code/android/
+[webrtc-ios-development]: https://webrtc.googlesource.com/src/+/main/docs/native-code/ios/
+[chromium-fuzz]: https://ci.chromium.org/p/chromium/g/chromium.fuzz/console
+[linux-bot]: https://ci.chromium.org/ui/p/chromium/builders/ci/Libfuzzer%20Upload%20Linux%20ASan/
+[libfuzzer-getting-started]: https://chromium.googlesource.com/chromium/src/+/main/testing/libfuzzer/getting_started_with_libfuzzer.md
+[fuzztest-getting-started]: https://chromium.googlesource.com/chromium/src/+/main/testing/libfuzzer/getting_started.md
+[webrtc-autoroller]: https://autoroll.skia.org/r/webrtc-chromium-autoroll