Fix missing shadows for tooltip and menu

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h"
 
 #include <X11/extensions/shape.h>
 #include <X11/extensions/XInput2.h>
 #include <X11/Xatom.h>
 #include <X11/Xregion.h>
@@ skipping 1138 matching lines @@
       window_type = atom_cache_.GetAtom("_NET_WM_WINDOW_TYPE_NORMAL");
       break;
   }
   // An in-activatable window should not interact with the system wm.
   if (!activatable_)
     swa.override_redirect = True;
 
   if (swa.override_redirect)
     attribute_mask |= CWOverrideRedirect;
 
-  Visual* visual;
-  int depth;
-  ui::ChooseVisualForWindow(true, &visual, &depth);
-  if (depth == 32) {
-    attribute_mask |= CWColormap;
-    swa.colormap =
-        XCreateColormap(xdisplay_, x_root_window_, visual, AllocNone);
+  bool enable_transparent_visuals =
+      params.type == Widget::InitParams::TYPE_DRAG ||
+      params.type == Widget::InitParams::TYPE_WINDOW;
 
-    // x.org will BadMatch if we don't set a border when the depth isn't the
-    // same as the parent depth.
-    attribute_mask |= CWBorderPixel;
-    swa.border_pixel = 0;
+  Visual* visual = CopyFromParent;
+  int depth = CopyFromParent;
+  if (enable_transparent_visuals) {
+    ui::ChooseVisualForWindow(enable_transparent_visuals, &visual, &depth);

[piman, 2016/08/24 17:21:49]

Ignoring the statics for a second, ChooseVisualForWindow would return the root
window's (i.e. the parent's) visual if enable_transparent_visuals is false.

So, could we fix ChooseVisualForWindow to cache separately the visuals for
transparent and opaque? I think it would make more sense: ChooseVisualForWindow
would choose the right visual based on enable_transparent_visuals, independent
of how it was called before. That way, we don't need to distribute the logic
between there and here.

+    if (depth == 32) {
+      attribute_mask |= CWColormap;
+      swa.colormap =
+          XCreateColormap(xdisplay_, x_root_window_, visual, AllocNone);
 
-    // A compositing manager is required to support transparency.
-    use_argb_visual_ =
-        XGetSelectionOwner(xdisplay_, atom_cache_.GetAtom("_NET_WM_CM_S0")) !=
-        None;
+      // x.org will BadMatch if we don't set a border when the depth isn't the
+      // same as the parent depth.
+      attribute_mask |= CWBorderPixel;
+      swa.border_pixel = 0;
+
+      // A compositing manager is required to support transparency.
+      use_argb_visual_ =
+          XGetSelectionOwner(xdisplay_, atom_cache_.GetAtom("_NET_WM_CM_S0")) !=
+          None;
+    }
   }
 
   bounds_in_pixels_ = ToPixelRect(params.bounds);
   bounds_in_pixels_.set_size(AdjustSize(bounds_in_pixels_.size()));
   xwindow_ = XCreateWindow(xdisplay_, x_root_window_, bounds_in_pixels_.x(),
                            bounds_in_pixels_.y(), bounds_in_pixels_.width(),
                            bounds_in_pixels_.height(),
                            0,  // border width
                            depth, InputOutput, visual, attribute_mask, &swa);
   if (ui::PlatformEventSource::GetInstance())
@@ skipping 908 matching lines @@
   if (linux_ui) {
     ui::NativeTheme* native_theme = linux_ui->GetNativeTheme(window);
     if (native_theme)
       return native_theme;
   }
 
   return ui::NativeThemeAura::instance();
 }
 
 }  // namespace views