cros: Break BaseScreenHandler into two classes.

chrome/browser/ui/webui/chromeos/login/host_pairing_screen_handler.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/ui/webui/chromeos/login/host_pairing_screen_handler.h"
 
 #include "base/command_line.h"
 #include "base/strings/string_util.h"
 #include "chrome/browser/chromeos/login/oobe_screen.h"
 #include "chrome/grit/generated_resources.h"
 #include "chromeos/chromeos_switches.h"
 #include "components/login/localized_values_builder.h"
 
 namespace chromeos {
 
 namespace {
 
 const char kJsScreenPath[] = "login.HostPairingScreen";
 
 const char kMethodContextChanged[] = "contextChanged";
 
 // Sent from JS when screen is ready to receive context updates.
 // TODO(dzhioev): Move 'contextReady' logic to the base screen handler when
 // all screens migrate to context-based communications.
 const char kCallbackContextReady[] = "contextReady";
 
 }  // namespace
 
-HostPairingScreenHandler::HostPairingScreenHandler() {
+HostPairingScreenHandler::HostPairingScreenHandler()
+    : BaseScreenHandler(kScreenId) {
   set_call_js_prefix(kJsScreenPath);
 }
 
 HostPairingScreenHandler::~HostPairingScreenHandler() {
   if (delegate_)
     delegate_->OnViewDestroyed(this);
 }
 
 void HostPairingScreenHandler::HandleContextReady() {
   js_context_ready_ = true;
@@ skipping 48 matching lines @@
 void HostPairingScreenHandler::RegisterMessages() {
   AddPrefixedCallback(kCallbackContextReady,
                       &HostPairingScreenHandler::HandleContextReady);
 }
 
 void HostPairingScreenHandler::Show() {
   if (!page_is_ready()) {
     show_on_init_ = true;
     return;
   }
-  ShowScreen(OobeScreen::SCREEN_OOBE_HOST_PAIRING);
+  ShowScreen(kScreenId);
 }
 
 void HostPairingScreenHandler::Hide() {
 }
 
 void HostPairingScreenHandler::SetDelegate(Delegate* delegate) {
   delegate_ = delegate;
   if (page_is_ready())
     Initialize();
 }
 
 void HostPairingScreenHandler::OnContextChanged(
     const base::DictionaryValue& diff) {
   if (!js_context_ready_) {
     context_cache_.ApplyChanges(diff, NULL);
     return;
   }
   CallJS(kMethodContextChanged, diff);
 }
 
 }  // namespace chromeos