Fix the flash for any new created window.

The flash is because the child window created by GLSurfaceGLX doesn't
match the visual of parent window. Fix the problem by always creating
parent window with the same visual.

Bug: 956061
Change-Id: I88cb65b4a0313be6fdea1bd8d6770d351500ccbb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1591946Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Commit-Queue: Peng Huang <penghuang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#656497}

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

@@ -1426,24 +1426,15 @@ void DesktopWindowTreeHostX11::InitX11Window(
   if (override_redirect_)
     attribute_mask |= CWOverrideRedirect;
 
-  bool enable_transparent_visuals;
-  switch (params.opacity) {
-    case Widget::InitParams::OPAQUE_WINDOW:
-      enable_transparent_visuals = false;
-      break;
-    case Widget::InitParams::TRANSLUCENT_WINDOW:
-      enable_transparent_visuals = true;
-      break;
-    case Widget::InitParams::INFER_OPACITY:
-    default:
-      enable_transparent_visuals = params.type == Widget::InitParams::TYPE_DRAG;
-  }
-
   Visual* visual = CopyFromParent;
   int depth = CopyFromParent;
   Colormap colormap = CopyFromParent;
+
+  // GLSurfaceGLX always create child window with alpha channel. If the parent
+  // window doesn't have alpha channel, it causes flash, so always request argb
+  // visual.
   ui::XVisualManager::GetInstance()->ChooseVisualForWindow(
-      enable_transparent_visuals, &visual, &depth, &colormap,
+      true /* want_argb_visual */, &visual, &depth, &colormap,
       &use_argb_visual_);
 
   if (colormap != CopyFromParent) {