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 8761f7f5cc83857e0164d4f81eb654e02b4c555d..2ff3fdf3a20bd00aec5c0db0c8d9d1c6e0f7789d 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 {
 
@@ -3705,5 +3711,39 @@ TEST_F(WidgetTest, WindowModalOwnerDestroyedEnabledTest) {
 
 #endif  // defined(OS_WIN)
 
+#if !defined(OS_CHROMEOS)
+// Test to ensure that the transparency state of the native window maches
+// what returns ShouldWindowContentsBeTransparent(). On Linux it also checks
+// that it returns true when --enable-transparent-visuals is passed.
+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;
+  init_params.native_widget =
+      CreatePlatformDesktopNativeWidgetImpl(init_params, &widget, nullptr);
+  widget.Init(init_params);
+
+  EXPECT_EQ(IsNativeWindowTransparent(widget.GetNativeWindow()),
+            widget.ShouldWindowContentsBeTransparent());

[sadrul, 2016/06/14 15:45:31]

You should need to at least set Widget::InitParams::opacity to
TRANSLUCENT_WINDOW?

[Julien Isorce Samsung, 2016/06/14 16:02:40]

Yes you are right. Somehow the test still succeeds with default value
INFER_OPACITY and same with OPAQUE_WINDOW. (and with default value it seems to
succeed on all platforms)

+
+#if defined(USE_X11)
+  EXPECT_TRUE(widget.ShouldWindowContentsBeTransparent());
+#endif
+}
+#endif  // !defined(OS_CHROMEOS)
+
 }  // namespace test
 }  // namespace views