Added member data to classes to support download 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 d7b5211cca4f9c5cad700d19fcbacf145c7f87ee..392dc481c4bb105767e6b02cc7738d08d22b2c48 100644
--- a/content/browser/download/download_resource_handler.cc
+++ b/content/browser/download/download_resource_handler.cc
@@ -51,7 +51,9 @@ DownloadResourceHandler::DownloadResourceHandler(
       save_info_(save_info),
       buffer_(new content::DownloadBuffer),
       rdh_(rdh),
-      is_paused_(false) {
+      is_paused_(false),
+      was_interrupted_(false),
+      interrupted_bytes_(0) {
   DCHECK(dl_id.IsValid());
   download_stats::RecordDownloadCount(download_stats::UNTHROTTLED_COUNT);
 }
@@ -94,7 +96,7 @@ bool DownloadResourceHandler::OnResponseStarted(int request_id,
   info->url_chain = request_->url_chain();
   info->referrer_url = GURL(request_->referrer());
   info->start_time = base::Time::Now();
-  info->received_bytes = 0;
+  info->received_bytes = was_interrupted_ ? interrupted_bytes_ : 0;
   info->total_bytes = content_length_;
   info->state = DownloadItem::IN_PROGRESS;
   info->download_id = download_id_.local();
@@ -102,12 +104,23 @@ bool DownloadResourceHandler::OnResponseStarted(int request_id,
   info->content_disposition = content_disposition_;
   info->mime_type = response->response_head.mime_type;
   download_stats::RecordDownloadMimeType(info->mime_type);
+  info->continued_download = was_interrupted_;
 
   DownloadRequestHandle request_handle(rdh_, global_id_.child_id,
                                        render_view_id_, global_id_.request_id);
 
-  // TODO(ahendrickson) -- Get the last modified time and etag, so we can
-  // resume downloading.
+  // If we're starting a new download, get the last modified time and etag.

[Randy Smith (Not in Mondays), 2011/10/31 18:46:43]

Why don't we get these all the time?  Why conditionalize?  My sense is that we
need them on both start and restart to compare against each other, but even if
we don't, the code's simpler if we always get them.

[ahendrickson, 2011/11/13 21:15:20]

Done.

+  if (was_interrupted_) {
+    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;
+    }
+  }
 
   CallStartedCB(net::OK);