Shorten delay before mounting SMB share

Currently, we wait until the first batch of shares is returned from host
discovery before attempting to Mount a share so that name resolution can
be performed. This change switches to using the GatherSharesInNetwork method that
takes a HostDiscoveryResponse callback so that the delay is shortened.

Bug: chromium:757625
Change-Id: I22cf5fd48bdcc633fa4d7f2f08b1e6f7e10af764
Reviewed-on: https://chromium-review.googlesource.com/1211947
Commit-Queue: Bailey Berro <baileyberro@chromium.org>
Reviewed-by: Scott Chen <scottchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590069}

chrome/browser/ui/webui/settings/chromeos/smb_handler.cc

@@ -92,17 +92,22 @@ void SmbHandler::HandleStartDiscovery(const base::ListValue* args) {
     return;
   }
 
-  service->GatherSharesInNetwork(base::BindRepeating(
-      &SmbHandler::HandleGatherSharesResponse, weak_ptr_factory_.GetWeakPtr()));
+  service->GatherSharesInNetwork(
+      base::BindOnce(&SmbHandler::HandleDiscoveryDone,
+                     weak_ptr_factory_.GetWeakPtr()),
+      base::BindRepeating(&SmbHandler::HandleGatherSharesResponse,
+                          weak_ptr_factory_.GetWeakPtr()));
 }
 
-void SmbHandler::HandleGatherSharesResponse(
-    const std::vector<smb_client::SmbUrl>& shares_gathered) {
+void SmbHandler::HandleDiscoveryDone() {
   host_discovery_done_ = true;
   if (!stored_mount_call_.is_null()) {
     std::move(stored_mount_call_).Run();
   }
+}
 
+void SmbHandler::HandleGatherSharesResponse(
+    const std::vector<smb_client::SmbUrl>& shares_gathered) {
   AllowJavascript();
   FireWebUIListener("on-shares-found", BuildShareList(shares_gathered));
 }

chrome/browser/ui/webui/settings/chromeos/smb_handler.h

@@ -42,6 +42,9 @@ class SmbHandler : public ::settings::SettingsPageUIHandler {
   void HandleGatherSharesResponse(
       const std::vector<smb_client::SmbUrl>& shares_gathered);
 
+  // Callback handler that indicates discovery is complete.
+  void HandleDiscoveryDone();
+
   bool host_discovery_done_ = false;
   base::OnceClosure stored_mount_call_;
   Profile* const profile_;