Get rid of recently added rtc_openssl_is_boringssl build argument.

It's unlikely to be used, so just rely on rtc_build_ssl instead.

No-Try: True
Bug: webrtc:11410
Change-Id: I74049bebfdde61b713eb187a48eabedf04da9369
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/197040
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32826}
diff --git a/rtc_base/BUILD.gn b/rtc_base/BUILD.gn
index 8762bfb..6f5331f 100644
--- a/rtc_base/BUILD.gn
+++ b/rtc_base/BUILD.gn
@@ -960,7 +960,8 @@
     "unique_id_generator.h",
   ]
 
-  if (rtc_openssl_is_boringssl) {
+  # If we are building the SSL library ourselves, we know it's BoringSSL.
+  if (rtc_build_ssl) {
     sources += [
       "boringssl_certificate.cc",
       "boringssl_certificate.h",
diff --git a/webrtc.gni b/webrtc.gni
index 2f6e77d..05a230c 100644
--- a/webrtc.gni
+++ b/webrtc.gni
@@ -227,10 +227,6 @@
   rtc_libvpx_build_vp9 = !build_with_mozilla
   rtc_build_opus = !build_with_mozilla
   rtc_build_ssl = !build_with_mozilla
-
-  # Can be set to true if rtc_build_ssl is false, but externally provided
-  # openssl library is boringssl, to enable the use of boringssl-specific code.
-  rtc_openssl_is_boringssl = !build_with_mozilla
   rtc_build_usrsctp = !build_with_mozilla
 
   # Enable libevent task queues on platforms that support it.