Add control to use If-Range header for range request.

content/browser/download/download_worker.cc

Index: content/browser/download/download_worker.cc
diff --git a/content/browser/download/download_worker.cc b/content/browser/download/download_worker.cc
index 35639b5738c9b34a7e5321dee68033ae981fb836..47ef9d2847259fb253771e206f93954fb3d7134d 100644
--- a/content/browser/download/download_worker.cc
+++ b/content/browser/download/download_worker.cc
@@ -89,14 +89,18 @@ void DownloadWorker::OnUrlDownloaderStarted(
     return;
   }
 
-  // TODO(xingliu): Add the interrupt reason and metric data for precondition
-  // failure. Make DownloadRequestCore know if it should return error if the
-  // the server gives a different part of the content, e.g. "If-Match" return
-  // http 200.
+  // TODO(xingliu): Add metric for error handling.
   if (create_info->result !=
       DownloadInterruptReason::DOWNLOAD_INTERRUPT_REASON_NONE) {
     VLOG(kVerboseLevel) << "Parallel download sub-request failed. reason = "
                         << create_info->result;
+
+    // Ignore HTTP 416 for the workers.
+    if (create_info->result ==
+        DownloadInterruptReason::DOWNLOAD_INTERRUPT_REASON_SERVER_NO_RANGE) {
+      return;
+    }
+
     delegate_->OnServerResponseError(this, create_info->result);
     return;
   }