Allow top-level frames to request any USB device.

chrome/browser/ui/webui/print_preview/extension_printer_handler_unittest.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/webui/print_preview/extension_printer_handler.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
@@ skipping 548 matching lines @@
   extensions::DevicePermissionsManager* permissions_manager =
       extensions::DevicePermissionsManager::Get(env_.profile());
   permissions_manager->AllowUsbDevice(extension_2->id(), device0);
 
   size_t call_count = 0;
   std::unique_ptr<base::ListValue> printers;
   bool is_done = false;
   extension_printer_handler_->StartGetPrinters(
       base::Bind(&RecordPrinterList, &call_count, &printers, &is_done));
 
+  base::RunLoop().RunUntilIdle();
+
   FakePrinterProviderAPI* fake_api = GetPrinterProviderAPI();
   ASSERT_TRUE(fake_api);
   ASSERT_EQ(1u, fake_api->pending_get_printers_count());
 
   EXPECT_EQ(1u, call_count);
   EXPECT_FALSE(is_done);
   EXPECT_TRUE(printers.get());
   EXPECT_EQ(2u, printers->GetSize());
   std::unique_ptr<base::DictionaryValue> extension_1_entry(
       DictionaryBuilder()
@@ skipping 428 matching lines @@
       DictionaryBuilder()
           .Set("id", "printer1")
           .Set("name", "Printer 1")
           .Build());
 
   fake_api->TriggerNextUsbPrinterInfoCallback(*original_printer_info);
 
   EXPECT_EQ(0u, call_count);
   EXPECT_FALSE(printer_info.get());
 }