rtc_use_h264 flag for building OpenH264/FFmpeg

build_overrides/webrtc.gni

Index: build_overrides/webrtc.gni
diff --git a/build_overrides/webrtc.gni b/build_overrides/webrtc.gni
index 0869397bef2689b689cd362d77cffbc8e5b6b1f2..78b55d5db445b681a8130fb20d46c70e4c6b0566 100644
--- a/build_overrides/webrtc.gni
+++ b/build_overrides/webrtc.gni
@@ -20,3 +20,8 @@ rtc_include_pulse_audio = true
 # Chromium uses its own IO handling, so the internal ADM is only built for
 # standalone WebRTC.
 rtc_include_internal_audio_device = true
+
+# OVERRIDE DEFAULT VALUES FOR SAKE OF TRYBOTS, NOT TO LAND
+if (!is_ios) {
+  use_h264 = true
+}