Fixing warning C4267 on Win (more_configs).

This is a follow-up of https://webrtc-review.googlesource.com/c/src/+/12921.

Bug: chromium:759980
Change-Id: Ifd39adb6541c0c7e0337f587a8b34b84a07331ed
Reviewed-on: https://webrtc-review.googlesource.com/13122
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20341}
diff --git a/modules/audio_coding/codecs/isac/unittest.cc b/modules/audio_coding/codecs/isac/unittest.cc
index 7a811cf..df78ab7 100644
--- a/modules/audio_coding/codecs/isac/unittest.cc
+++ b/modules/audio_coding/codecs/isac/unittest.cc
@@ -17,6 +17,7 @@
 #include "modules/audio_coding/codecs/isac/main/include/audio_encoder_isac.h"
 #include "modules/audio_coding/neteq/tools/input_audio_file.h"
 #include "rtc_base/buffer.h"
+#include "rtc_base/safe_conversions.h"
 #include "test/gtest.h"
 #include "test/testsupport/fileutils.h"
 
@@ -163,10 +164,12 @@
     const int send_time = elapsed_time_ms * (sample_rate_hz / 1000);
     EXPECT_EQ(0, T::UpdateBwEstimate(
                      encdec, bitstream1.data(), bitstream1.size(), i, send_time,
-                     channel1.Send(send_time, bitstream1.size())));
+                     channel1.Send(send_time,
+                                   rtc::checked_cast<int>(bitstream1.size()))));
     EXPECT_EQ(0, T::UpdateBwEstimate(
                      dec, bitstream2.data(), bitstream2.size(), i, send_time,
-                     channel2.Send(send_time, bitstream2.size())));
+                     channel2.Send(send_time,
+                                   rtc::checked_cast<int>(bitstream2.size()))));
 
     // 3. Decode, and get new BW info from the separate decoder.
     ASSERT_EQ(0, T::SetDecSampRate(encdec, sample_rate_hz));