Stop using the g_browser_process->net_log() when creating download manager

NetLog is going to be moved into the network service process.
This CL remove download system from using the browser process netlog.
The CL switches download to use its own netlog,
so we won't block Matt's effort to clean things up.
A follow up CL will switch all the netlog usage to TraceEvent.


BUG=767450

Change-Id: Id42bfa9d74624c383cf0479db0b1fe2c3732ba70
Reviewed-on: https://chromium-review.googlesource.com/741553
Commit-Queue: Min Qin <[email protected]>
Reviewed-by: Matt Menke <[email protected]>
Reviewed-by: David Trainor <[email protected]>
Reviewed-by: John Abd-El-Malek <[email protected]>
Cr-Commit-Position: refs/heads/master@{#512378}
diff --git a/content/browser/download/download_manager_impl.cc b/content/browser/download/download_manager_impl.cc
index cd82ef85..474e2b2 100644
--- a/content/browser/download/download_manager_impl.cc
+++ b/content/browser/download/download_manager_impl.cc
@@ -284,15 +284,14 @@
 
 }  // namespace
 
-DownloadManagerImpl::DownloadManagerImpl(net::NetLog* net_log,
-                                         BrowserContext* browser_context)
+DownloadManagerImpl::DownloadManagerImpl(BrowserContext* browser_context)
     : item_factory_(new DownloadItemFactoryImpl()),
       file_factory_(new DownloadFileFactory()),
       shutdown_needed_(true),
       initialized_(false),
       browser_context_(browser_context),
       delegate_(nullptr),
-      net_log_(net_log),
+      net_log_(nullptr),
       weak_factory_(this) {
   DCHECK(browser_context);
 }