[Downloads] Some UMA for downloads resumption.

content/browser/download/download_resource_handler.cc

Index: content/browser/download/download_resource_handler.cc
diff --git a/content/browser/download/download_resource_handler.cc b/content/browser/download/download_resource_handler.cc
index 2a02cf926dfc1f159e3d91b4f62c6e685ca3fef0..3b4844e6e68ee33651ffd4904ca71fc5a43dec0a 100644
--- a/content/browser/download/download_resource_handler.cc
+++ b/content/browser/download/download_resource_handler.cc
@@ -171,11 +171,10 @@ bool DownloadResourceHandler::OnResponseStarted(
   const net::HttpResponseHeaders* headers = request_->response_headers();
   if (headers) {
     std::string last_modified_hdr;
-    std::string etag;
     if (headers->EnumerateHeader(NULL, "Last-Modified", &last_modified_hdr))
       info->last_modified = last_modified_hdr;
-    if (headers->EnumerateHeader(NULL, "ETag", &etag))
-      info->etag = etag;
+    if (headers->EnumerateHeader(NULL, "ETag", &etag_))
+      info->etag = etag_;
 
     int status = headers->response_code();
     if (2 == status / 100  && status != net::HTTP_PARTIAL_CONTENT) {
@@ -373,7 +372,7 @@ bool DownloadResourceHandler::OnResponseCompleted(
     }
   }
 
-  RecordAcceptsRanges(accept_ranges_, bytes_read_);
+  RecordAcceptsRanges(accept_ranges_, bytes_read_, etag_);
   RecordNetworkBlockage(
       base::TimeTicks::Now() - download_start_time_, total_pause_time_);