mash: Move directly linked NewWindowDelegate to mojom::NewWindowClient.

ash/common/test/wm_shell_test_api.h

Index: ash/common/test/wm_shell_test_api.h
diff --git a/ash/common/test/wm_shell_test_api.h b/ash/common/test/wm_shell_test_api.h
index 07ab6fff2e916e0978fb233de0b52d38f41418fb..1e46ba94a3b48e58ac3296088afe60295fad96dd 100644
--- a/ash/common/test/wm_shell_test_api.h
+++ b/ash/common/test/wm_shell_test_api.h
@@ -13,6 +13,10 @@ namespace ash {
 
 class SystemTrayDelegate;
 
+namespace mojom {
+class NewWindowClient;
+}
+
 // Test API to access the internal state of the singleton WmShell.
 class WmShellTestApi {
  public:
@@ -21,6 +25,8 @@ class WmShellTestApi {
 
   void SetSystemTrayDelegate(std::unique_ptr<SystemTrayDelegate> delegate);
 
+  void SetNewWindowClient(std::unique_ptr<mojom::NewWindowClient> client);
+
  private:
   DISALLOW_COPY_AND_ASSIGN(WmShellTestApi);
 };