Make File-Picker modal on Linux

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h
index 1d3cbd7f8773b6c052e5c2115c3bec5ea79338c5..9f76c9584f0f2ab93cab6859ac26c818678ac5d3 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h
@@ -15,6 +15,7 @@
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
+#include "ui/aura/scoped_window_targeter.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/base/cursor/cursor_loader_x11.h"
 #include "ui/events/platform/platform_event_dispatcher.h"
@@ -50,6 +51,17 @@ class VIEWS_EXPORT DesktopWindowTreeHostX11
       DesktopNativeWidgetAura* desktop_native_widget_aura);
   ~DesktopWindowTreeHostX11() override;
 
+  class ScopedHandle {
+   public:
+    explicit ScopedHandle(const base::Closure& destroy_callback);
+    ~ScopedHandle();
+    void CancelCallback();
+
+   private:
+    base::Closure destroy_callback_;
+    DISALLOW_COPY_AND_ASSIGN(ScopedHandle);
+  };
+
   // A way of converting an X11 |xid| host window into a |content_window_|.
   static aura::Window* GetContentWindowForXID(XID xid);
 
@@ -86,6 +98,13 @@ class VIEWS_EXPORT DesktopWindowTreeHostX11
   // internal list of open windows.
   static void CleanUpWindowList(void (*func)(aura::Window* window));
 
+  // Disables event listening to make |dialog| modal.
+  std::unique_ptr<ScopedHandle> DisableEventListening(XID dialog);
+
+  // Returns XID of dialog currently displayed. When it returns 0,
+  // there is no dialog on the host window.
+  XID GetModalDialog();
+
  protected:
   // Overridden from DesktopWindowTreeHost:
   void Init(aura::Window* content_window,
@@ -246,6 +265,9 @@ class VIEWS_EXPORT DesktopWindowTreeHostX11
   gfx::Rect ToDIPRect(const gfx::Rect& rect_in_pixels) const;
   gfx::Rect ToPixelRect(const gfx::Rect& rect_in_dip) const;
 
+  // Enables event listening after closing |dialog|.
+  void EnableEventListening();
+
   // X11 things
   // The display and the native X window hosting the root window.
   XDisplay* xdisplay_;
@@ -348,6 +370,12 @@ class VIEWS_EXPORT DesktopWindowTreeHostX11
 
   base::CancelableCallback<void()> delayed_resize_task_;
 
+  std::unique_ptr<aura::ScopedWindowTargeter> targeter_for_modal_;
+
+  XID modal_dialog_xid_;
+
+  ScopedHandle* scoped_handle_;
+
   base::WeakPtrFactory<DesktopWindowTreeHostX11> close_widget_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopWindowTreeHostX11);