Change file op |ssize_t|s to FileOperationResult

util/net/http_transport_mac.mm

Index: util/net/http_transport_mac.mm
diff --git a/util/net/http_transport_mac.mm b/util/net/http_transport_mac.mm
index 971a99867fd948e9d5687a0d0dae9a9f0dfe4a29..aad505d531d2bc74397ea2fc04b3cfa0264b6738 100644
--- a/util/net/http_transport_mac.mm
+++ b/util/net/http_transport_mac.mm
@@ -22,6 +22,7 @@
 #include "base/strings/stringprintf.h"
 #include "base/strings/sys_string_conversions.h"
 #include "third_party/apple_cf/CFStreamAbstract.h"
+#include "util/file/file_io.h"
 #include "util/misc/implicit_cast.h"
 #include "util/net/http_body.h"
 
@@ -93,7 +94,8 @@ class HTTPBodyStreamCFReadStream {
       return 0;
     }
 
-    ssize_t bytes_read = GetStream(info)->GetBytesBuffer(buffer, buffer_length);
+    FileOperationResult bytes_read =
+        GetStream(info)->GetBytesBuffer(buffer, buffer_length);
     if (bytes_read < 0) {
       error->error = -1;
       error->domain = kCFStreamErrorDomainCustom;