Stop using ByteSize (deprecated) to get the size of a proto message.

The method ByteSize has been deprecated [1], this CL switches to
ByteSizeLong.

[1] - https://cs.chromium.org/chromium/src/third_party/protobuf/src/google/protobuf/message_lite.h?l=252&rcl=ac47edd22c481fcfe119769d6b7abf365abea8fa

Bug: None
Change-Id: I1ba622df52f47719a5beda6d230cb603a0163d43
Reviewed-on: https://webrtc-review.googlesource.com/27021
Reviewed-by: Tommi <tommi@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20952}
diff --git a/modules/audio_processing/audio_processing_unittest.cc b/modules/audio_processing/audio_processing_unittest.cc
index 4da0621..5984ed7 100644
--- a/modules/audio_processing/audio_processing_unittest.cc
+++ b/modules/audio_processing/audio_processing_unittest.cc
@@ -33,6 +33,7 @@
 #include "rtc_base/checks.h"
 #include "rtc_base/gtest_prod_util.h"
 #include "rtc_base/ignore_wundef.h"
+#include "rtc_base/numerics/safe_conversions.h"
 #include "rtc_base/numerics/safe_minmax.h"
 #include "rtc_base/protobuf_utils.h"
 #include "rtc_base/refcountedobject.h"
@@ -243,7 +244,7 @@
   FILE* file = fopen(filename.c_str(), "wb");
   ASSERT_TRUE(file != NULL);
 
-  int32_t size = msg.ByteSize();
+  int32_t size = rtc::checked_cast<int32_t>(msg.ByteSizeLong());
   ASSERT_GT(size, 0);
   std::unique_ptr<uint8_t[]> array(new uint8_t[size]);
   ASSERT_TRUE(msg.SerializeToArray(array.get(), size));