chore: cherry-pick 3fbd1dca6a4d from libvpx (#40026)

* chore: cherry-pick 3fbd1dca6a4d from libvpx

* build: update patches config

* chore: update patches

patches/config.json

@@ -31,5 +31,7 @@
 
   "src/electron/patches/webrtc": "src/third_party/webrtc",
 
-  "src/electron/patches/libwebp": "src/third_party/libwebp/src"
+  "src/electron/patches/libwebp": "src/third_party/libwebp/src",
+
+  "src/electron/patches/libvpx": "src/third_party/libvpx/source/libvpx"
 }

patches/libvpx/.patches

@@ -0,0 +1 @@
+cherry-pick-3fbd1dca6a4d.patch

patches/libvpx/cherry-pick-3fbd1dca6a4d.patch

@@ -0,0 +1,27 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: James Zern <jzern@google.com>
+Date: Mon, 25 Sep 2023 18:55:59 -0700
+Subject: VP8: disallow thread count changes
+
+Currently allocations are done at encoder creation time. Going from
+threaded to non-threaded would cause a crash.
+
+Bug: chromium:1486441
+Change-Id: Ie301c2a70847dff2f0daae408fbef1e4d42e73d4
+
+diff --git a/vp8/encoder/onyx_if.c b/vp8/encoder/onyx_if.c
+index 94fb6e256e8f4f1077aa6e2aef84e3bc7070da0f..f68339d2b4f4b2ca654a835cc56c537fb5e7d260 100644
+--- a/vp8/encoder/onyx_if.c
++++ b/vp8/encoder/onyx_if.c
+@@ -1443,6 +1443,11 @@ void vp8_change_config(VP8_COMP *cpi, VP8_CONFIG *oxcf) {
+   last_h = cpi->oxcf.Height;
+   prev_number_of_layers = cpi->oxcf.number_of_layers;
+
++  if (cpi->initial_width) {
++    // TODO(https://crbug.com/1486441): Allow changing thread counts; the
++    // allocation is done once in vp8_create_compressor().
++    oxcf->multi_threaded = cpi->oxcf.multi_threaded;
++  }
+   cpi->oxcf = *oxcf;
+
+   switch (cpi->oxcf.Mode) {