Re-submit of https://codereview.chromium.org/356613002

chrome/browser/extensions/api/gcd_private/gcd_private_api.cc

 // Copyright 2014 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/extensions/api/gcd_private/gcd_private_api.h"
 
 #include "base/lazy_instance.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/local_discovery/cloud_device_list.h"
 #include "chrome/browser/local_discovery/cloud_print_printer_list.h"
@@ skipping 150 matching lines @@
   for (GCDDeviceMap::iterator i = known_devices_.begin();
        i != known_devices_.end();
        i++) {
     EventRouter::Get(browser_context_)
         ->BroadcastEvent(MakeDeviceRemovedEvent(i->second->device_id));
   }
 
   known_devices_.clear();
 }
 
+bool GcdPrivateAPI::QueryForDevices() {
+  if (!privet_device_lister_)
+    return false;
+
+  privet_device_lister_->DiscoverNewDevices(true);
+
+  return true;
+}
+
 // static
 void GcdPrivateAPI::SetGCDApiFlowFactoryForTests(
     GCDApiFlowFactoryForTests* factory) {
   g_gcd_api_flow_factory = factory;
 }
 
 GcdPrivateGetCloudDeviceListFunction::GcdPrivateGetCloudDeviceListFunction() {
 }
+
 GcdPrivateGetCloudDeviceListFunction::~GcdPrivateGetCloudDeviceListFunction() {
 }
 
 bool GcdPrivateGetCloudDeviceListFunction::RunAsync() {
   requests_succeeded_ = 0;
   requests_failed_ = 0;
 
   printer_list_ = MakeGCDApiFlow(GetProfile());
   device_list_ = MakeGCDApiFlow(GetProfile());
 
@@ skipping 62 matching lines @@
 
 GcdPrivateQueryForNewLocalDevicesFunction::
     GcdPrivateQueryForNewLocalDevicesFunction() {
 }
 
 GcdPrivateQueryForNewLocalDevicesFunction::
     ~GcdPrivateQueryForNewLocalDevicesFunction() {
 }
 
 bool GcdPrivateQueryForNewLocalDevicesFunction::RunSync() {
-  return false;
+  GcdPrivateAPI* gcd_api =
+      BrowserContextKeyedAPIFactory<GcdPrivateAPI>::Get(GetProfile());
+
+  if (!gcd_api)
+    return false;
+
+  if (!gcd_api->QueryForDevices()) {
+    error_ =
+        "You must first subscribe to onDeviceStateChanged or onDeviceRemoved "
+        "notifications";
+    return false;
+  }
+
+  return true;
 }
 
 GcdPrivateStartSetupFunction::GcdPrivateStartSetupFunction() {
 }
 
 GcdPrivateStartSetupFunction::~GcdPrivateStartSetupFunction() {
 }
 
 bool GcdPrivateStartSetupFunction::RunAsync() {
   return false;
@@ skipping 85 matching lines @@
 }
 
 GcdPrivateGetCommandsListFunction::~GcdPrivateGetCommandsListFunction() {
 }
 
 bool GcdPrivateGetCommandsListFunction::RunAsync() {
   return false;
 }
 
 }  // namespace extensions