Revert of Move DefaultActivationClient to wm/core

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 34183db5921f946f8e0aa3d31acfb74e57714cdd..b300dcfce9d3d3aa48160dcad24b8c6847f76e92 100644
--- a/ui/aura/test/aura_test_helper.cc
+++ b/ui/aura/test/aura_test_helper.cc
@@ -7,6 +7,7 @@
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "ui/aura/client/aura_constants.h"
+#include "ui/aura/client/default_activation_client.h"
 #include "ui/aura/client/default_capture_client.h"
 #include "ui/aura/client/focus_client.h"
 #include "ui/aura/env.h"
@@ -70,6 +71,8 @@
   focus_client_.reset(new TestFocusClient);
   client::SetFocusClient(root_window(), focus_client_.get());
   stacking_client_.reset(new TestWindowTreeClient(root_window()));
+  activation_client_.reset(
+      new client::DefaultActivationClient(root_window()));
   capture_client_.reset(new client::DefaultCaptureClient(root_window()));
   test_input_method_.reset(new ui::DummyInputMethod);
   root_window()->SetProperty(
@@ -85,6 +88,7 @@
   teardown_called_ = true;
   test_input_method_.reset();
   stacking_client_.reset();
+  activation_client_.reset();
   capture_client_.reset();
   focus_client_.reset();
   client::SetFocusClient(root_window(), NULL);