Make mus_demo_unittests work with multiple root windows

services/ui/demo/mus_demo_unittests.cc

Index: services/ui/demo/mus_demo_unittests.cc
diff --git a/services/ui/demo/mus_demo_unittests.cc b/services/ui/demo/mus_demo_unittests.cc
index 9fdb8107a2c0aff014de2d237164dce0aaecd753..827e92520e567371b008e7fac58373a76ccfeef9 100644
--- a/services/ui/demo/mus_demo_unittests.cc
+++ b/services/ui/demo/mus_demo_unittests.cc
@@ -18,8 +18,10 @@ namespace {
 
 const char kTestAppName[] = "mus_demo_unittests";
 
-void RunCallback(bool* success, const base::Closure& callback, bool result) {
-  *success = result;
+void RunCallback(uint64_t* root_window_count,
+                 const base::Closure& callback,
+                 uint64_t result) {
+  *root_window_count = result;
   callback.Run();
 }
 
@@ -33,6 +35,26 @@ class MusDemoTest : public service_manager::test::ServiceTest {
     ServiceTest::SetUp();
   }
 
+ protected:
+  uint64_t StartDemoAndCountDrawnWindows() {
+    connector()->Connect("mus_demo");
+
+    ::ui::mojom::WindowServerTestPtr test_interface;
+    connector()->BindInterface(ui::mojom::kServiceName, &test_interface);
+
+    base::RunLoop run_loop;
+    uint64_t root_window_count = 0;
+    // TODO(kylechar): Fix WindowServer::CreateTreeForWindowManager so that the
+    // WindowTree has the correct name instead of an empty name.
+    // TODO(tonikitoo,fwang): Also fix the WindowTree name for MusDemoExternal.
+    test_interface->EnsureClientHasDrawnRootWindows(
+        "",  // WindowTree name is empty.
+        base::Bind(&RunCallback, &root_window_count, run_loop.QuitClosure()));
+    run_loop.Run();
+
+    return root_window_count;
+  }
+
  private:
   DISALLOW_COPY_AND_ASSIGN(MusDemoTest);
 };
@@ -40,21 +62,17 @@ class MusDemoTest : public service_manager::test::ServiceTest {
 }  // namespace
 
 TEST_F(MusDemoTest, CheckMusDemoDraws) {
-  connector()->Connect("mus_demo");
-
-  ::ui::mojom::WindowServerTestPtr test_interface;
-  connector()->BindInterface(ui::mojom::kServiceName, &test_interface);
-
-  base::RunLoop run_loop;
-  bool success = false;
-  // TODO(kylechar): Fix WindowServer::CreateTreeForWindowManager so that the
-  // WindowTree has the correct name instead of an empty name.
-  test_interface->EnsureClientHasDrawnWindow(
-      "",  // WindowTree name is empty.
-      base::Bind(&RunCallback, &success, run_loop.QuitClosure()));
-  run_loop.Run();
-  EXPECT_TRUE(success);
+  EXPECT_EQ(1u, StartDemoAndCountDrawnWindows());
+}
+
+#if defined(USE_OZONE) && !defined(OS_CHROMEOS)
+TEST_F(MusDemoTest, CheckMusDemoMultipleWindows) {
+  uint64_t expected_root_window_count = 5;
+  base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
+      "external-window-count", std::to_string(expected_root_window_count));
+  EXPECT_EQ(expected_root_window_count, StartDemoAndCountDrawnWindows());
 }
+#endif  // defined(USE_OZONE) && !defined(OS_CHROMEOS)
 
 }  // namespace demo
 }  // namespace ui