Update crashpad_handler man page to document all options

handler/mac/crash_report_upload_thread.cc

Index: handler/mac/crash_report_upload_thread.cc
diff --git a/handler/mac/crash_report_upload_thread.cc b/handler/mac/crash_report_upload_thread.cc
index a4e4607d0c57bf4d6c96a1ad85e9bde5b0b02e93..5333c78d180e02d476dfb4a3434515220363e0a2 100644
--- a/handler/mac/crash_report_upload_thread.cc
+++ b/handler/mac/crash_report_upload_thread.cc
@@ -226,9 +226,11 @@ void CrashReportUploadThread::ProcessPendingReport(
   Settings* const settings = database_->GetSettings();
 
   bool uploads_enabled;
-  if (!settings->GetUploadsEnabled(&uploads_enabled) || !uploads_enabled) {
-    // If uploads are disabled or the upload-enabled state can’t be determined,
-    // don’t attempt to upload the new report.
+  if (!settings->GetUploadsEnabled(&uploads_enabled) ||
+      !uploads_enabled ||
+      url_.empty()) {
+    // If the upload-enabled state can’t be determined, uploads are disabled, or
+    // there’s no URL to upload to, don’t attempt to upload the new report.
     database_->SkipReportUpload(report.uuid);
     return;
   }