RTC_[D]CHECK_op: Remove superfluous casts

webrtc/modules/audio_device/fine_audio_buffer.cc

Index: webrtc/modules/audio_device/fine_audio_buffer.cc
diff --git a/webrtc/modules/audio_device/fine_audio_buffer.cc b/webrtc/modules/audio_device/fine_audio_buffer.cc
index 7fffdd14fbcf2014b96d45869d1131a46f22c06c..c0ee15e6630e14a20d7fcc5c6cf84836392818c9 100644
--- a/webrtc/modules/audio_device/fine_audio_buffer.cc
+++ b/webrtc/modules/audio_device/fine_audio_buffer.cc
@@ -106,7 +106,7 @@ void FineAudioBuffer::GetPlayoutData(int8_t* buffer) {
   // If playout_cached_bytes_ is larger than the cache buffer, uninitialized
   // memory will be read.
   RTC_CHECK_LE(playout_cached_bytes_, bytes_per_10_ms_);
-  RTC_CHECK_EQ(static_cast<size_t>(-bytes_left), playout_cached_bytes_);
+  RTC_CHECK_EQ(-bytes_left, playout_cached_bytes_);
   playout_cached_buffer_start_ = 0;
   memcpy(playout_cache_buffer_.get(), cache_ptr, playout_cached_bytes_);
 }