Hooked up NetLog to DownloadItem, DownloadFile, and FileStream.

content/browser/tab_contents/web_drag_source_mac.mm

Index: content/browser/tab_contents/web_drag_source_mac.mm
diff --git a/content/browser/tab_contents/web_drag_source_mac.mm b/content/browser/tab_contents/web_drag_source_mac.mm
index ba84e6de5b9c22d61ae4745eaf03fbbf13415ad9..02f8293b84789d89f54dade26d3790c4de4a09fe 100644
--- a/content/browser/tab_contents/web_drag_source_mac.mm
+++ b/content/browser/tab_contents/web_drag_source_mac.mm
@@ -20,6 +20,7 @@
 #include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/tab_contents/tab_contents.h"
 #include "content/public/browser/content_browser_client.h"
+#include "content/public/common/content_client.h"
 #include "content/public/common/url_constants.h"
 #include "net/base/file_stream.h"
 #include "net/base/net_util.h"
@@ -323,7 +324,8 @@ void PromiseWriterHelper(const WebDropData& drop_data,
   // UI thread on OSX, it should be reasonable to let it happen.
   base::ThreadRestrictions::ScopedAllowIO allowIO;
   FileStream* fileStream =
-      drag_download_util::CreateFileStreamForDrop(&filePath);
+      drag_download_util::CreateFileStreamForDrop(
+          &filePath, content::GetContentClient()->browser()->GetNetLog());
   if (!fileStream)
     return nil;