Change FocusSynchronizer to maintain active focus client and window.

ui/aura/test/aura_test_helper.cc

Index: ui/aura/test/aura_test_helper.cc
diff --git a/ui/aura/test/aura_test_helper.cc b/ui/aura/test/aura_test_helper.cc
index ccbd85342fa274db54259999d02b6655d95d30ec..7df499a026f6cfd8c4434b3223186fa6d74b8711 100644
--- a/ui/aura/test/aura_test_helper.cc
+++ b/ui/aura/test/aura_test_helper.cc
@@ -12,6 +12,7 @@
 #include "ui/aura/env.h"
 #include "ui/aura/input_state_lookup.h"
 #include "ui/aura/mus/capture_synchronizer.h"
+#include "ui/aura/mus/focus_synchronizer.h"
 #include "ui/aura/mus/window_port_mus.h"
 #include "ui/aura/mus/window_tree_client.h"
 #include "ui/aura/test/env_test_helper.h"
@@ -112,7 +113,6 @@ void AuraTestHelper::SetUp(ui::ContextFactory* context_factory,
   // Tests assume they can set the mouse location on Env() and have it reflected
   // in tests.
   env_helper.SetAlwaysUseLastMouseLocation(true);
-  Env::GetInstance()->SetActiveFocusClient(focus_client_.get(), nullptr);
   Env::GetInstance()->set_context_factory(context_factory);
   Env::GetInstance()->set_context_factory_private(context_factory_private);
   // Unit tests generally don't want to query the system, rather use the state
@@ -159,7 +159,6 @@ void AuraTestHelper::TearDown() {
     display::Screen::SetScreenInstance(nullptr);
   test_screen_.reset();
 
-  Env::GetInstance()->SetActiveFocusClient(nullptr, nullptr);
   window_tree_client_setup_.reset();
   focus_client_.reset();
   capture_client_.reset();
@@ -197,6 +196,8 @@ void AuraTestHelper::InitWindowTreeClient() {
   window_tree_client_setup_->InitForWindowManager(window_tree_delegate_,
                                                   window_manager_delegate_);
   window_tree_client_ = window_tree_client_setup_->window_tree_client();
+  window_tree_client_->focus_synchronizer()->SetActiveFocusClient(
+      focus_client_.get(), nullptr);
   window_tree_client_->capture_synchronizer()->AttachToCaptureClient(
       capture_client_.get());
 }