[ozone/x11] Enabled the global menu bar for Ozone/X11.

The global menu bar (aka DbusMenu) was originally available only on
non-Ozone, but we can enable it on Ozone/X11 as well.

This CL does some code cleanup and enables the menu for Ozone/X11.

Bug: 990756
Change-Id: I2cd4a504474d31d7e3ced350a8afeeff62e4a778
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2289772
Commit-Queue: Alexander Dunaev <adunaev@igalia.com>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791140}

chrome/browser/ui/BUILD.gn

@@ -24,6 +24,7 @@ import("//printing/buildflags/buildflags.gni")
 import("//rlz/buildflags/buildflags.gni")
 import("//third_party/protobuf/proto_library.gni")
 import("//ui/base/ui_features.gni")
+import("//ui/ozone/ozone.gni")
 import("//ui/views/features.gni")
 
 # Reset sources_assignment_filter for the BUILD.gn file to prevent
@@ -3067,12 +3068,19 @@ static_library("ui") {
       ]
     }
 
-    if (use_x11) {
+    if (use_dbus && (use_x11 || ozone_platform_x11)) {
       sources += [
         "views/frame/global_menu_bar_registrar_x11.cc",
         "views/frame/global_menu_bar_registrar_x11.h",
         "views/frame/global_menu_bar_x11.cc",
         "views/frame/global_menu_bar_x11.h",
+      ]
+      defines += [ "USE_DBUS_MENU" ]
+      deps += [ "//ui/gfx/x" ]
+    }
+
+    if (use_x11) {
+      sources += [
         "views/frame/native_browser_frame_factory_aurax11.cc",
         "views/javascript_app_modal_dialog_views_x11.cc",
         "views/javascript_app_modal_dialog_views_x11.h",
@@ -3080,7 +3088,6 @@ static_library("ui") {
         "views/javascript_app_modal_event_blocker_x11.h",
       ]
       deps += [
-        "//components/dbus/menu",
         "//ui/events/devices",
         "//ui/events/devices/x11",
         "//ui/events/platform/x11",

chrome/browser/ui/views/frame/browser_desktop_window_tree_host_linux.cc

@@ -14,8 +14,23 @@
 #include "chrome/browser/ui/views/frame/desktop_browser_frame_aura_linux.h"
 #include "chrome/browser/ui/views/tabs/tab_strip.h"
 #include "ui/base/ui_base_features.h"
+#include "ui/ozone/public/ozone_platform.h"
 #include "ui/platform_window/extensions/x11_extension.h"
 
+namespace {
+
+bool CreateGlobalMenuBar() {
+#if defined(USE_OZONE)
+  return ui::OzonePlatform::GetInstance()
+      ->GetPlatformProperties()
+      .supports_global_application_menus;
+#else
+  return true;
+#endif
+}
+
+}  // namespace
+
 ////////////////////////////////////////////////////////////////////////////////
 // BrowserDesktopWindowTreeHostLinux, public:
 
@@ -76,17 +91,19 @@ void BrowserDesktopWindowTreeHostLinux::Init(
     const views::Widget::InitParams& params) {
   DesktopWindowTreeHostLinuxImpl::Init(std::move(params));
 
-#if defined(USE_X11)
-  // We have now created our backing X11 window. We now need to (possibly)
-  // alert Unity that there's a menu bar attached to it.
-  if (!features::IsUsingOzonePlatform())
-    global_menu_bar_x11_ =
-        std::make_unique<GlobalMenuBarX11>(browser_view_, this);
+#if defined(USE_DBUS_MENU)
+  // We have now created our backing X11 window.  We now need to (possibly)
+  // alert the desktop environment that there's a menu bar attached to it.
+
+  if (CreateGlobalMenuBar()) {
+    global_menu_bar_x11_ = std::make_unique<GlobalMenuBarX11>(
+        browser_view_, GetAcceleratedWidget());
+  }
 #endif
 }
 
 void BrowserDesktopWindowTreeHostLinux::CloseNow() {
-#if defined(USE_X11)
+#if defined(USE_DBUS_MENU)
   global_menu_bar_x11_.reset();
 #endif
   DesktopWindowTreeHostLinuxImpl::CloseNow();

chrome/browser/ui/views/frame/browser_desktop_window_tree_host_linux.h

@@ -8,8 +8,11 @@
 #include "base/macros.h"
 #include "chrome/browser/ui/views/frame/browser_desktop_window_tree_host.h"
 
-#if defined(USE_X11)
+#if defined(USE_DBUS_MENU)
 #include "chrome/browser/ui/views/frame/global_menu_bar_x11.h"  // nogncheck
+#endif
+
+#if defined(USE_X11)
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h"  // nogncheck
 #else
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host_linux.h"  // nogncheck
@@ -63,7 +66,7 @@ class BrowserDesktopWindowTreeHostLinux
   BrowserView* browser_view_ = nullptr;
   BrowserFrame* browser_frame_ = nullptr;
 
-#if defined(USE_X11)
+#if defined(USE_DBUS_MENU)
   // Each browser frame maintains its own menu bar object because the lower
   // level dbus protocol associates a xid to a menu bar; we can't map multiple
   // xids to the same menu bar.

chrome/browser/ui/views/frame/global_menu_bar_registrar_x11.cc

@@ -45,7 +45,7 @@ void GlobalMenuBarRegistrarX11::OnMenuBarDestroyed(GlobalMenuBarX11* menu) {
     dbus::MethodCall method_call(kAppMenuRegistrarInterface,
                                  "UnregisterWindow");
     dbus::MessageWriter writer(&method_call);
-    writer.AppendUint32(static_cast<uint32_t>(menu->window()));
+    writer.AppendUint32(menu->browser_frame_xid());
     registrar_proxy_->CallMethod(&method_call,
                                  dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
                                  base::DoNothing());
@@ -90,7 +90,7 @@ void GlobalMenuBarRegistrarX11::RegisterMenu(GlobalMenuBarX11* menu) {
   menus_[menu] = kRegistered;
   dbus::MethodCall method_call(kAppMenuRegistrarInterface, "RegisterWindow");
   dbus::MessageWriter writer(&method_call);
-  writer.AppendUint32(static_cast<uint32_t>(menu->window()));
+  writer.AppendUint32(menu->browser_frame_xid());
   writer.AppendObjectPath(dbus::ObjectPath(menu->GetPath()));
   registrar_proxy_->CallMethod(
       &method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT, base::DoNothing());

chrome/browser/ui/views/frame/global_menu_bar_x11.cc

@@ -206,11 +206,11 @@ struct GlobalMenuBarX11::HistoryItem {
 };
 
 GlobalMenuBarX11::GlobalMenuBarX11(BrowserView* browser_view,
-                                   aura::WindowTreeHost* host)
+                                   uint32_t browser_frame_xid)
     : browser_(browser_view->browser()),
       profile_(browser_->profile()),
       browser_view_(browser_view),
-      window_(static_cast<x11::Window>(host->GetAcceleratedWidget())),
+      browser_frame_xid_(browser_frame_xid),
       tab_restore_service_(nullptr),
       last_command_id_(kFirstUnreservedCommandId - 1) {
   GlobalMenuBarRegistrarX11::GetInstance()->OnMenuBarCreated(this);
@@ -285,8 +285,7 @@ void GlobalMenuBarX11::Initialize(DbusMenu::InitializedCallback callback) {
 }
 
 std::string GlobalMenuBarX11::GetPath() const {
-  return base::StringPrintf("/com/canonical/menu/%X",
-                            static_cast<uint32_t>(window_));
+  return base::StringPrintf("/com/canonical/menu/%X", browser_frame_xid_);
 }
 
 ui::SimpleMenuModel* GlobalMenuBarX11::BuildStaticMenu(

chrome/browser/ui/views/frame/global_menu_bar_x11.h

@@ -26,8 +26,6 @@
 #include "components/sessions/core/tab_restore_service_observer.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/base/models/simple_menu_model.h"
-#include "ui/gfx/x/x11.h"
-#include "ui/gfx/x/x11_types.h"
 
 namespace ui {
 class Accelerator;
@@ -38,10 +36,12 @@ class BrowserView;
 struct GlobalMenuBarCommand;
 class Profile;
 
-// Controls the Mac style menu bar on Unity.
+// Controls the Mac style menu bar on Linux desktop environments.
 //
-// Unity has an Apple-like menu bar at the top of the screen that changes
-// depending on the active window.
+// Unity had a MacOS-like menu bar at the top of the screen that changed
+// depending on the active window.  Unity has been discontinued but the menu
+// survived and is usually referred to as DBus AppMenu.  There is support for it
+// in KDE Plasma in form of a widget that can be inserted into a panel.
 class GlobalMenuBarX11 : public AvatarMenuObserver,
                          public BrowserListObserver,
                          public CommandObserver,
@@ -49,7 +49,7 @@ class GlobalMenuBarX11 : public AvatarMenuObserver,
                          public sessions::TabRestoreServiceObserver,
                          public ui::SimpleMenuModel::Delegate {
  public:
-  GlobalMenuBarX11(BrowserView* browser_view, aura::WindowTreeHost* host);
+  GlobalMenuBarX11(BrowserView* browser_view, uint32_t browser_frame_xid);
   ~GlobalMenuBarX11() override;
 
   void Initialize(DbusMenu::InitializedCallback callback);
@@ -57,7 +57,7 @@ class GlobalMenuBarX11 : public AvatarMenuObserver,
   // Creates the object path for DbusemenuServer which is attached to |window|.
   std::string GetPath() const;
 
-  x11::Window window() const { return window_; }
+  uint32_t browser_frame_xid() const { return browser_frame_xid_; }
 
  private:
   struct HistoryItem;
@@ -130,7 +130,12 @@ class GlobalMenuBarX11 : public AvatarMenuObserver,
   Browser* const browser_;
   Profile* profile_;
   BrowserView* browser_view_;
-  x11::Window window_;
+  // XID of the browser's frame window that owns this menu.  Deliberately stored
+  // as plain int (and not as x11::Window) because it is never used for any
+  // calls to the X server, but it is always used for building string paths and
+  // messages, for which it is converted to int (see GetPath() and calls to our
+  // browser_frame_xid() in GlobalMenuBarRegistrarX11).
+  const uint32_t browser_frame_xid_;
 
   // Has Initialize() been called?
   bool initialized_ = false;

ui/ozone/platform/x11/ozone_platform_x11.cc

@@ -71,7 +71,8 @@ constexpr OzonePlatform::PlatformProperties kX11PlatformProperties{
     // events. See GLSurfaceGLX and https://crbug.com/326995.
     .message_pump_type_for_gpu = base::MessagePumpType::UI,
     .supports_vulkan_swap_chain = true,
-    .platform_shows_drag_image = false};
+    .platform_shows_drag_image = false,
+    .supports_global_application_menus = true};
 
 // Singleton OzonePlatform implementation for X11 platform.
 class OzonePlatformX11 : public OzonePlatform,

ui/ozone/public/ozone_platform.h

@@ -96,6 +96,10 @@ class COMPONENT_EXPORT(OZONE) OzonePlatform {
 
     // If true, the platform shows and updates the drag image.
     bool platform_shows_drag_image = true;
+
+    // Linux only, but see a TODO in BrowserDesktopWindowTreeHostLinux.
+    // Determines whether the platform supports the global application menu.
+    bool supports_global_application_menus = false;
   };
 
   // Properties available in the host process after initialization.