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/neteq/neteq_impl_unittest.cc b/modules/audio_coding/neteq/neteq_impl_unittest.cc
index a6e48c7..45d7f26 100644
--- a/modules/audio_coding/neteq/neteq_impl_unittest.cc
+++ b/modules/audio_coding/neteq/neteq_impl_unittest.cc
@@ -483,7 +483,7 @@
         decoded[i] = next_value_++;
       }
       *speech_type = kSpeech;
-      return encoded_len;
+      return rtc::checked_cast<int>(encoded_len);
     }
 
     void Reset() override { next_value_ = 1; }
@@ -1312,7 +1312,7 @@
       decoded[i] = next_value_++;
     }
     *speech_type = speech_type_;
-    return decoded_len;
+    return rtc::checked_cast<int>(decoded_len);
   }
 
   void Reset() override { next_value_ = 1; }