Windows: Fix hidden dropdowns when the window is topmost (issue #1468)

Also add a --always-on-top flag to cefclient to allow easier testing of this
behavior on Windows and Linux.

libcef/browser/native/browser_platform_delegate_native_linux.cc

@@ -81,8 +81,8 @@ bool CefBrowserPlatformDelegateNativeLinux::CreateHostWindow() {
   // Add a reference that will be released in BrowserDestroyed().
   browser_->AddRef();
 
-  CefWindowDelegateView* delegate_view =
-      new CefWindowDelegateView(GetBackgroundColor());
+  CefWindowDelegateView* delegate_view = new CefWindowDelegateView(
+      GetBackgroundColor(), window_x11_->TopLevelAlwaysOnTop());
   delegate_view->Init(window_info_.window, browser_->web_contents(),
                       gfx::Rect(gfx::Point(), rect.size()));
 

libcef/browser/native/browser_platform_delegate_native_win.cc

@@ -194,8 +194,15 @@ bool CefBrowserPlatformDelegateNativeWin::CreateHostWindow() {
   point =
       gfx::ToFlooredPoint(gfx::ScalePoint(gfx::PointF(point), 1.0f / scale));
 
+  // Stay on top if top-most window hosting the web view is topmost.
+  HWND top_level_window = GetAncestor(window_info_.window, GA_ROOT);
+  DWORD top_level_window_ex_styles =
+      GetWindowLongPtr(top_level_window, GWL_EXSTYLE);
+  bool always_on_top =
+      (top_level_window_ex_styles & WS_EX_TOPMOST) == WS_EX_TOPMOST;
+
   CefWindowDelegateView* delegate_view =
-      new CefWindowDelegateView(GetBackgroundColor());
+      new CefWindowDelegateView(GetBackgroundColor(), always_on_top);
   delegate_view->Init(window_info_.window, browser_->web_contents(),
                       gfx::Rect(0, 0, point.x(), point.y()));
 

libcef/browser/native/window_delegate_view.cc

@@ -12,8 +12,11 @@
 #include "ui/views/layout/fill_layout.h"
 #include "ui/views/widget/widget.h"
 
-CefWindowDelegateView::CefWindowDelegateView(SkColor background_color)
-    : background_color_(background_color), web_view_(NULL) {}
+CefWindowDelegateView::CefWindowDelegateView(SkColor background_color,
+                                             bool always_on_top)
+    : background_color_(background_color),
+      web_view_(NULL),
+      always_on_top_(always_on_top) {}
 
 void CefWindowDelegateView::Init(gfx::AcceleratedWidget parent_widget,
                                  content::WebContents* web_contents,
@@ -44,6 +47,8 @@ void CefWindowDelegateView::Init(gfx::AcceleratedWidget parent_widget,
   // CefBrowserHostImpl::PlatformSetFocus.
   params.activatable = views::Widget::InitParams::ACTIVATABLE_YES;
 
+  params.keep_on_top = always_on_top_;
+
   // Results in a call to InitContent().
   widget->Init(params);
 

libcef/browser/native/window_delegate_view.h

@@ -20,7 +20,7 @@ class WebView;
 // will be deleted automatically when the associated root window is destroyed.
 class CefWindowDelegateView : public views::WidgetDelegateView {
  public:
-  explicit CefWindowDelegateView(SkColor background_color);
+  CefWindowDelegateView(SkColor background_color, bool always_on_top);
 
   // Create the Widget and associated root window.
   void Init(gfx::AcceleratedWidget parent_widget,
@@ -43,6 +43,7 @@ class CefWindowDelegateView : public views::WidgetDelegateView {
  private:
   SkColor background_color_;
   views::WebView* web_view_;
+  bool always_on_top_;
 
   DISALLOW_COPY_AND_ASSIGN(CefWindowDelegateView);
 };

libcef/browser/native/window_x11.cc

@@ -396,3 +396,34 @@ void CefWindowX11::ContinueFocus() {
     browser_->SetFocus(true);
   focus_pending_ = false;
 }
+
+bool CefWindowX11::TopLevelAlwaysOnTop() const {
+  ::Window toplevel_window = FindToplevelParent(xdisplay_, xwindow_);
+
+  Atom state_atom = gfx::GetAtom("_NET_WM_STATE");
+  Atom state_keep_above = gfx::GetAtom("_NET_WM_STATE_KEEP_ABOVE");
+  Atom* states;
+
+  Atom actual_type;
+  int actual_format;
+  unsigned long num_items;
+  unsigned long bytes_after;
+
+  XGetWindowProperty(xdisplay_, toplevel_window, state_atom, 0, 1024,
+                     x11::False, XA_ATOM, &actual_type, &actual_format,
+                     &num_items, &bytes_after,
+                     reinterpret_cast<unsigned char**>(&states));
+
+  bool always_on_top = false;
+
+  for (unsigned long i = 0; i < num_items; ++i) {
+    if (states[i] == state_keep_above) {
+      always_on_top = true;
+      break;
+    }
+  }
+
+  XFree(states);
+
+  return always_on_top;
+}

libcef/browser/native/window_x11.h

@@ -52,6 +52,8 @@ class CefWindowX11 : public ui::PlatformEventDispatcher {
   ::Window xwindow() const { return xwindow_; }
   gfx::Rect bounds() const { return bounds_; }
 
+  bool TopLevelAlwaysOnTop() const;
+
  private:
   void ContinueFocus();
 

tests/cefclient/browser/root_window.h

@@ -23,6 +23,9 @@ namespace client {
 struct RootWindowConfig {
   RootWindowConfig();
 
+  // If true the window will always display above other windows.
+  bool always_on_top;
+
   // If true the window will show controls.
   bool with_controls;
 

tests/cefclient/browser/root_window_gtk.cc

@@ -51,6 +51,7 @@ void MaximizeWindow(GtkWindow* window) {
 
 RootWindowGtk::RootWindowGtk()
     : with_controls_(false),
+      always_on_top_(false),
       with_osr_(false),
       with_extension_(false),
       is_popup_(false),
@@ -84,6 +85,7 @@ void RootWindowGtk::Init(RootWindow::Delegate* delegate,
 
   delegate_ = delegate;
   with_controls_ = config.with_controls;
+  always_on_top_ = config.always_on_top;
   with_osr_ = config.with_osr;
   with_extension_ = config.with_extension;
   start_rect_ = config.bounds;
@@ -275,6 +277,10 @@ void RootWindowGtk::CreateRootWindow(const CefBrowserSettings& settings,
   window_ = gtk_window_new(GTK_WINDOW_TOPLEVEL);
   CHECK(window_);
 
+  if (always_on_top_) {
+    gtk_window_set_keep_above(GTK_WINDOW(window_), TRUE);
+  }
+
   gtk_window_set_default_size(GTK_WINDOW(window_), width, height);
   g_signal_connect(G_OBJECT(window_), "focus-in-event",
                    G_CALLBACK(&RootWindowGtk::WindowFocusIn), this);

tests/cefclient/browser/root_window_gtk.h

@@ -125,6 +125,7 @@ class RootWindowGtk : public RootWindow, public BrowserWindow::Delegate {
   // After initialization all members are only accessed on the main thread.
   // Members set during initialization.
   bool with_controls_;
+  bool always_on_top_;
   bool with_osr_;
   bool with_extension_;
   bool is_popup_;

tests/cefclient/browser/root_window_views.cc

@@ -21,6 +21,7 @@ static const char* kDefaultImageCache[] = {"menu_icon", "window_icon"};
 
 RootWindowViews::RootWindowViews()
     : with_controls_(false),
+      always_on_top_(false),
       with_extension_(false),
       initially_hidden_(false),
       is_popup_(false),
@@ -42,6 +43,7 @@ void RootWindowViews::Init(RootWindow::Delegate* delegate,
 
   delegate_ = delegate;
   with_controls_ = config.with_controls;
+  always_on_top_ = config.always_on_top;
   with_extension_ = config.with_extension;
   initially_hidden_ = config.initially_hidden;
   if (initially_hidden_ && !config.source_bounds.IsEmpty()) {
@@ -239,6 +241,7 @@ void RootWindowViews::OnViewsWindowCreated(CefRefPtr<ViewsWindow> window) {
   CEF_REQUIRE_UI_THREAD();
   DCHECK(!window_);
   window_ = window;
+  window_->SetAlwaysOnTop(always_on_top_);
 
   if (!pending_extensions_.empty()) {
     window_->OnExtensionsChanged(pending_extensions_);

tests/cefclient/browser/root_window_views.h

@@ -104,6 +104,7 @@ class RootWindowViews : public RootWindow,
   // unless otherwise indicated.
   // Members set during initialization.
   bool with_controls_;
+  bool always_on_top_;
   bool with_extension_;
   bool initially_hidden_;
   CefRefPtr<CefWindow> parent_window_;

tests/cefclient/browser/root_window_win.cc

@@ -103,6 +103,7 @@ int GetURLBarHeight(HWND hwnd) {
 
 RootWindowWin::RootWindowWin()
     : with_controls_(false),
+      always_on_top_(false),
       with_osr_(false),
       with_extension_(false),
       is_popup_(false),
@@ -152,6 +153,7 @@ void RootWindowWin::Init(RootWindow::Delegate* delegate,
 
   delegate_ = delegate;
   with_controls_ = config.with_controls;
+  always_on_top_ = config.always_on_top;
   with_osr_ = config.with_osr;
   with_extension_ = config.with_extension;
 
@@ -333,6 +335,7 @@ void RootWindowWin::CreateRootWindow(const CefBrowserSettings& settings,
   CHECK(find_message_id_);
 
   const DWORD dwStyle = WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN;
+  const DWORD dwExStyle = always_on_top_ ? WS_EX_TOPMOST : 0;
 
   int x, y, width, height;
   if (::IsRectEmpty(&start_rect_)) {
@@ -341,7 +344,7 @@ void RootWindowWin::CreateRootWindow(const CefBrowserSettings& settings,
   } else {
     // Adjust the window size to account for window frame and controls.
     RECT window_rect = start_rect_;
-    ::AdjustWindowRectEx(&window_rect, dwStyle, with_controls_, 0);
+    ::AdjustWindowRectEx(&window_rect, dwStyle, with_controls_, dwExStyle);
 
     x = start_rect_.left;
     y = start_rect_.top;
@@ -352,8 +355,8 @@ void RootWindowWin::CreateRootWindow(const CefBrowserSettings& settings,
   browser_settings_ = settings;
 
   // Create the main window initially hidden.
-  CreateWindow(window_class.c_str(), window_title.c_str(), dwStyle, x, y, width,
-               height, NULL, NULL, hInstance, this);
+  CreateWindowEx(dwExStyle, window_class.c_str(), window_title.c_str(), dwStyle,
+                 x, y, width, height, NULL, NULL, hInstance, this);
   CHECK(hwnd_);
 
   if (!called_enable_non_client_dpi_scaling_ && IsProcessPerMonitorDpiAware()) {

tests/cefclient/browser/root_window_win.h

@@ -112,6 +112,7 @@ class RootWindowWin : public RootWindow, public BrowserWindow::Delegate {
   // After initialization all members are only accessed on the main thread.
   // Members set during initialization.
   bool with_controls_;
+  bool always_on_top_;
   bool with_osr_;
   bool with_extension_;
   bool is_popup_;

tests/cefclient/browser/views_window.cc

@@ -222,6 +222,13 @@ void ViewsWindow::SetFullscreen(bool fullscreen) {
   }
 }
 
+void ViewsWindow::SetAlwaysOnTop(bool on_top) {
+  CEF_REQUIRE_UI_THREAD();
+  if (window_) {
+    window_->SetAlwaysOnTop(on_top);
+  }
+}
+
 void ViewsWindow::SetLoadingState(bool isLoading,
                                   bool canGoBack,
                                   bool canGoForward) {

tests/cefclient/browser/views_window.h

@@ -112,6 +112,7 @@ class ViewsWindow : public CefBrowserViewDelegate,
   void SetTitle(const std::string& title);
   void SetFavicon(CefRefPtr<CefImage> image);
   void SetFullscreen(bool fullscreen);
+  void SetAlwaysOnTop(bool on_top);
   void SetLoadingState(bool isLoading, bool canGoBack, bool canGoForward);
   void SetDraggableRegions(const std::vector<CefDraggableRegion>& regions);
   void TakeFocus(bool next);

tests/cefclient/cefclient_gtk.cc

@@ -130,6 +130,7 @@ int RunMain(int argc, char* argv[]) {
   test_runner::RegisterSchemeHandlers();
 
   RootWindowConfig window_config;
+  window_config.always_on_top = command_line->HasSwitch(switches::kAlwaysOnTop);
   window_config.with_controls =
       !command_line->HasSwitch(switches::kHideControls);
   window_config.with_osr = settings.windowless_rendering_enabled ? true : false;

tests/cefclient/cefclient_win.cc

@@ -95,6 +95,7 @@ int RunMain(HINSTANCE hInstance, int nCmdShow) {
   test_runner::RegisterSchemeHandlers();
 
   RootWindowConfig window_config;
+  window_config.always_on_top = command_line->HasSwitch(switches::kAlwaysOnTop);
   window_config.with_controls =
       !command_line->HasSwitch(switches::kHideControls);
   window_config.with_osr = settings.windowless_rendering_enabled ? true : false;

tests/shared/common/client_switches.cc

@@ -37,6 +37,7 @@ const char kFilterURL[] = "filter-url";
 const char kUseViews[] = "use-views";
 const char kHideFrame[] = "hide-frame";
 const char kHideControls[] = "hide-controls";
+const char kAlwaysOnTop[] = "always-on-top";
 const char kHideTopMenu[] = "hide-top-menu";
 const char kWidevineCdmPath[] = "widevine-cdm-path";
 const char kSslClientCertificate[] = "ssl-client-certificate";

tests/shared/common/client_switches.h

@@ -31,6 +31,7 @@ extern const char kFilterURL[];
 extern const char kUseViews[];
 extern const char kHideFrame[];
 extern const char kHideControls[];
+extern const char kAlwaysOnTop[];
 extern const char kHideTopMenu[];
 extern const char kWidevineCdmPath[];
 extern const char kSslClientCertificate[];