Make DesktopWindowTreeHostX11::ShouldWindowContentsBeTransparent() relies on argb visual flag

ui/views/widget/widget_unittest.cc

Index: ui/views/widget/widget_unittest.cc
diff --git a/ui/views/widget/widget_unittest.cc b/ui/views/widget/widget_unittest.cc
index 3dfd3572eb13c4c8a35543682d3651ba3ac60d6f..af6a7e518754288d91ad07d487920a802d19e1f5 100644
--- a/ui/views/widget/widget_unittest.cc
+++ b/ui/views/widget/widget_unittest.cc
@@ -7,6 +7,7 @@
 #include <set>
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
@@ -47,6 +48,11 @@
 #include "base/mac/mac_util.h"
 #endif
 
+#if defined(USE_X11) && !defined(OS_CHROMEOS)
+#include "ui/base/x/x11_util_internal.h"  // nogncheck
+#include "ui/gfx/x/x11_switches.h"  // nogncheck
+#endif
+
 namespace views {
 namespace test {
 
@@ -3716,5 +3722,68 @@ TEST_F(WidgetTest, WindowModalOwnerDestroyedEnabledTest) {
 
 #endif  // defined(OS_WIN)
 
+#if !defined(OS_CHROMEOS)
+namespace {
+
+// An observer that registers the transparent flag of a widget on creation.
+class WidgetTransparencyObserver : public WidgetObserver {
+ public:
+  WidgetTransparencyObserver() : transparent_(false) {}
+  ~WidgetTransparencyObserver() override {}
+
+  bool transparent() { return transparent_; }
+
+  // WidgetObserver:
+  void OnWidgetCreated(Widget* widget) override {
+    EXPECT_TRUE(widget->GetNativeWindow());
+    transparent_ =
+        WidgetTest::IsNativeWindowTransparent(widget->GetNativeWindow());
+  }
+
+ private:
+  bool transparent_;
+
+  DISALLOW_COPY_AND_ASSIGN(WidgetTransparencyObserver);
+};
+
+}  // namespace
+
+// Test to ensure that the aura Window remains transparent after its creation
+// has finished if transparent visuals are enabled.
+TEST_F(WidgetTest, Transparency_DesktopWidget) {
+#if defined(USE_X11)
+  // On Linux, transparent visuals is currently not activated by default.
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+  command_line->AppendSwitch(switches::kEnableTransparentVisuals);
+
+  int depth = 0;
+  ui::ChooseVisualForWindow(NULL, &depth);
+  EXPECT_EQ(depth, 32);
+#endif
+
+  Widget::InitParams init_params =
+      CreateParams(Widget::InitParams::TYPE_WINDOW);
+  init_params.show_state = ui::SHOW_STATE_NORMAL;
+  init_params.bounds = gfx::Rect(0, 0, 500, 500);
+  init_params.ownership = Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
+  Widget widget;
+  WidgetTransparencyObserver widget_observer;
+  init_params.native_widget =
+      CreatePlatformDesktopNativeWidgetImpl(init_params, &widget, nullptr);
+  widget.AddObserver(&widget_observer);
+  widget.Init(init_params);
+  widget.Show();
+
+  EXPECT_EQ(widget_observer.transparent(),
+            IsNativeWindowTransparent(widget.GetNativeWindow()));
+  EXPECT_EQ(widget_observer.transparent(),
+            widget.ShouldWindowContentsBeTransparent());
+
+#if defined(USE_X11)
+  EXPECT_TRUE(widget_observer.transparent());
+#endif
+}
+#endif  // !defined(OS_CHROMEOS)
+
 }  // namespace test
 }  // namespace views