Unescape ampersands in network names on network selection screen

MenuModel escapes all ampersands in menu item labels but on network selection
screen this name used not as real menu item so we need to unescape it back.

BUG=480457
TEST=manual

Review URL: https://codereview.chromium.org/1107343002

Cr-Commit-Position: refs/heads/master@{#327280}

chrome/browser/ui/webui/chromeos/login/network_dropdown.cc

@@ -6,6 +6,8 @@
 
 #include <string>
 
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "base/values.h"
 #include "chrome/browser/chromeos/login/ui/login_display_host.h"
@@ -86,7 +88,10 @@ base::ListValue* NetworkMenuWebUI::ConvertMenuModel(ui::MenuModel* model) {
       id = model->GetCommandIdAt(i);
     base::DictionaryValue* item = new base::DictionaryValue();
     item->SetInteger("id", id);
-    item->SetString("label", model->GetLabelAt(i));
+    base::string16 label = model->GetLabelAt(i);
+    ReplaceSubstringsAfterOffset(&label, 0, base::ASCIIToUTF16("&&"),
+                                 base::ASCIIToUTF16("&"));
+    item->SetString("label", label);
     gfx::Image icon;
     if (model->GetIconAt(i, &icon)) {
       SkBitmap icon_bitmap = icon.ToImageSkia()->GetRepresentation(