Fix formatting specifier for MSVC++ 2013 compatibility.

media/cast/sender/external_video_encoder.cc

Index: media/cast/sender/external_video_encoder.cc
diff --git a/media/cast/sender/external_video_encoder.cc b/media/cast/sender/external_video_encoder.cc
index 04226cf537e3c90e12ef0477f8a9f5cd667e4be3..ca389a5cb470dbb0f8884ffa5454e00910687857 100644
--- a/media/cast/sender/external_video_encoder.cc
+++ b/media/cast/sender/external_video_encoder.cc
@@ -318,7 +318,8 @@ class ExternalVideoEncoder::VEAClientImpl
 
         const char kZeroEncodeDetails[] = "zero-encode-details";
         const std::string details = base::StringPrintf(
-            "%c/%c,id=%" PRIu32 ",rtp=%" PRIu32 ",br=%d,q=%zu,act=%c,ref=%d",
+            ("%c/%c,id=%" PRIu32 ",rtp=%" PRIu32 ",br=%d,q=%" PRIuS
+             ",act=%c,ref=%d"),
             codec_profile_ == media::VP8PROFILE_ANY ? 'V' : 'H',
             key_frame ? 'K' : 'D', encoded_frame->frame_id,
             encoded_frame->rtp_timestamp, request.target_bit_rate / 1000,