x11: Remove x11-specific WindowEventFilter implementation

This cleanup CL removes views::X11WindowEventFilter class in favor of generic
views::WindowEventFilter by modifying DesktopWindowTreeHostX11 to implement
WmMoveResizeHandler interface. As part of Aura/X11 => Ozone/X11 migration, this
makes non-client event handling in DWTHX11 more like DWTHPlatform as well as
removes one more unneeded usage of Event::native_event() which contributes to
X11 PlatformEvent migration sub-task.

Bug: 965991
Test: Covered by tests (no behavioral change).
Change-Id: Ie4a6457a2c4b68a09cb3b5622c65b736d2d490eb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1772537Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Commit-Queue: Nick Yamane <nickdiego@igalia.com>
Cr-Commit-Position: refs/heads/master@{#691298}

ui/views/BUILD.gn

@@ -719,7 +719,6 @@ jumbo_component("views") {
           "widget/desktop_aura/x11_move_loop_delegate.h",
           "widget/desktop_aura/x11_topmost_window_finder.h",
           "widget/desktop_aura/x11_whole_screen_move_loop.h",
-          "widget/desktop_aura/x11_window_event_filter.h",
         ]
         sources += [
           "widget/desktop_aura/desktop_drag_drop_client_aurax11.cc",
@@ -729,7 +728,6 @@ jumbo_component("views") {
           "widget/desktop_aura/x11_desktop_window_move_client.cc",
           "widget/desktop_aura/x11_topmost_window_finder.cc",
           "widget/desktop_aura/x11_whole_screen_move_loop.cc",
-          "widget/desktop_aura/x11_window_event_filter.cc",
         ]
         if (use_atk) {
           sources += [

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

@@ -62,9 +62,9 @@
 #include "ui/views/widget/desktop_aura/desktop_native_cursor_manager.h"
 #include "ui/views/widget/desktop_aura/desktop_native_widget_aura.h"
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host_observer_x11.h"
+#include "ui/views/widget/desktop_aura/window_event_filter.h"
 #include "ui/views/widget/desktop_aura/x11_desktop_handler.h"
 #include "ui/views/widget/desktop_aura/x11_desktop_window_move_client.h"
-#include "ui/views/widget/desktop_aura/x11_window_event_filter.h"
 #include "ui/views/window/native_frame_view.h"
 #include "ui/wm/core/compound_event_filter.h"
 #include "ui/wm/core/window_util.h"
@@ -267,14 +267,19 @@ void DesktopWindowTreeHostX11::RemoveObserver(
   observer_list_.RemoveObserver(observer);
 }
 
-void DesktopWindowTreeHostX11::SwapNonClientEventHandler(
-    std::unique_ptr<ui::EventHandler> handler) {
-  wm::CompoundEventFilter* compound_event_filter =
-      desktop_native_widget_aura_->root_window_event_filter();
-  if (x11_non_client_event_filter_)
-    compound_event_filter->RemoveHandler(x11_non_client_event_filter_.get());
-  compound_event_filter->AddHandler(handler.get());
-  x11_non_client_event_filter_ = std::move(handler);
+void DesktopWindowTreeHostX11::AddNonClientEventFilter() {
+  if (non_client_event_filter_)
+    return;
+  non_client_event_filter_ = std::make_unique<WindowEventFilter>(this);
+  non_client_event_filter_->SetWmMoveResizeHandler(this);
+  window()->AddPreTargetHandler(non_client_event_filter_.get());
+}
+
+void DesktopWindowTreeHostX11::RemoveNonClientEventFilter() {
+  if (!non_client_event_filter_)
+    return;
+  window()->RemovePreTargetHandler(non_client_event_filter_.get());
+  non_client_event_filter_.reset();
 }
 
 void DesktopWindowTreeHostX11::CleanUpWindowList(
@@ -313,9 +318,7 @@ void DesktopWindowTreeHostX11::OnNativeWidgetCreated(
   // notify events.
   X11DesktopHandler::get();
 
-  // TODO(erg): Unify this code once the other consumer goes away.
-  SwapNonClientEventHandler(
-      std::unique_ptr<ui::EventHandler>(new X11WindowEventFilter(this)));
+  AddNonClientEventFilter();
   SetUseNativeFrame(params.type == Widget::InitParams::TYPE_WINDOW &&
                     !params.remove_standard_frame);
 
@@ -366,6 +369,7 @@ void DesktopWindowTreeHostX11::CloseNow() {
     return;
 
   ReleaseCapture();
+  RemoveNonClientEventFilter();
   native_widget_delegate_->OnNativeWidgetDestroying();
 
   // If we have children, close them. Use a copy for iteration because they'll
@@ -381,12 +385,6 @@ void DesktopWindowTreeHostX11::CloseNow() {
     window_parent_ = nullptr;
   }
 
-  // Remove the event listeners we've installed. We need to remove these
-  // because otherwise we get assert during ~WindowEventDispatcher().
-  desktop_native_widget_aura_->root_window_event_filter()->RemoveHandler(
-      x11_non_client_event_filter_.get());
-  x11_non_client_event_filter_.reset();
-
   // Destroy the compositor before destroying the |xwindow_| since shutdown
   // may try to swap, and the swap without a window causes an X error, which
   // causes a crash with in-process renderer.
@@ -1298,6 +1296,12 @@ void DesktopWindowTreeHostX11::InitX11Window(const Widget::InitParams& params) {
   OnAcceleratedWidgetAvailable();
 }
 
+void DesktopWindowTreeHostX11::DispatchHostWindowDragMovement(
+    int hittest,
+    const gfx::Point& pointer_location) {
+  x11_window_->WmMoveResize(hittest, pointer_location);
+}
+
 gfx::Size DesktopWindowTreeHostX11::AdjustSize(
     const gfx::Size& requested_size_in_pixels) {
   std::vector<display::Display> displays =

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h

@@ -25,6 +25,7 @@
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/x/x11_types.h"
+#include "ui/platform_window/platform_window_handler/wm_move_resize_handler.h"
 #include "ui/views/views_export.h"
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host.h"
 
@@ -34,7 +35,6 @@ class ImageSkia;
 
 namespace ui {
 enum class DomCode;
-class EventHandler;
 class KeyboardHook;
 class KeyEvent;
 class MouseEvent;
@@ -47,11 +47,13 @@ class DesktopDragDropClientAuraX11;
 class DesktopWindowTreeHostObserverX11;
 class NonClientFrameView;
 class X11DesktopWindowMoveClient;
+class WindowEventFilter;
 
 class VIEWS_EXPORT DesktopWindowTreeHostX11
     : public DesktopWindowTreeHost,
       public aura::WindowTreeHost,
       public ui::PlatformEventDispatcher,
+      public ui::WmMoveResizeHandler,
       public ui::XWindow::Delegate {
  public:
   DesktopWindowTreeHostX11(
@@ -85,8 +87,8 @@ class VIEWS_EXPORT DesktopWindowTreeHostX11
   void AddObserver(DesktopWindowTreeHostObserverX11* observer);
   void RemoveObserver(DesktopWindowTreeHostObserverX11* observer);
 
-  // Swaps the current handler for events in the non client view with |handler|.
-  void SwapNonClientEventHandler(std::unique_ptr<ui::EventHandler> handler);
+  void AddNonClientEventFilter();
+  void RemoveNonClientEventFilter();
 
   // Runs the |func| callback for each content-window, and deallocates the
   // internal list of open windows.
@@ -224,6 +226,11 @@ class VIEWS_EXPORT DesktopWindowTreeHostX11
   // initialization related to talking to the X11 server.
   void InitX11Window(const Widget::InitParams& params);
 
+  // Overridden from WmMoveResizeHandler
+  void DispatchHostWindowDragMovement(
+      int hittest,
+      const gfx::Point& pointer_location) override;
+
   // Creates an aura::WindowEventDispatcher to contain the content_window()
   // along with all aura client objects that direct behavior.
   aura::WindowEventDispatcher* InitDispatcher(const Widget::InitParams& params);
@@ -296,7 +303,7 @@ class VIEWS_EXPORT DesktopWindowTreeHostX11
 
   DesktopDragDropClientAuraX11* drag_drop_client_ = nullptr;
 
-  std::unique_ptr<ui::EventHandler> x11_non_client_event_filter_;
+  std::unique_ptr<WindowEventFilter> non_client_event_filter_;
   std::unique_ptr<X11DesktopWindowMoveClient> x11_window_move_client_;
 
   // TODO(beng): Consider providing an interface to DesktopNativeWidgetAura

ui/views/widget/desktop_aura/x11_window_event_filter.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/x11_window_event_filter.h"
-
-#include "ui/aura/client/aura_constants.h"
-#include "ui/aura/window.h"
-#include "ui/aura/window_delegate.h"
-#include "ui/aura/window_tree_host.h"
-#include "ui/base/hit_test_x11.h"
-#include "ui/base/x/x11_util.h"
-#include "ui/display/display.h"
-#include "ui/display/screen.h"
-#include "ui/events/event.h"
-#include "ui/events/event_utils.h"
-#include "ui/gfx/x/x11.h"
-#include "ui/gfx/x/x11_atom_cache.h"
-#include "ui/gfx/x/x11_types.h"
-#include "ui/views/linux_ui/linux_ui.h"
-#include "ui/views/widget/desktop_aura/desktop_window_tree_host.h"
-#include "ui/views/widget/native_widget_aura.h"
-#include "ui/views/widget/widget.h"
-
-namespace views {
-
-X11WindowEventFilter::X11WindowEventFilter(
-    DesktopWindowTreeHost* window_tree_host)
-    : WindowEventFilter(window_tree_host),
-      xdisplay_(gfx::GetXDisplay()),
-      xwindow_(window_tree_host->AsWindowTreeHost()->GetAcceleratedWidget()),
-      x_root_window_(DefaultRootWindow(xdisplay_)) {}
-
-X11WindowEventFilter::~X11WindowEventFilter() = default;
-
-void X11WindowEventFilter::MaybeDispatchHostWindowDragMovement(
-    int hittest,
-    ui::MouseEvent* event) {
-  if (event->IsLeftMouseButton() && event->native_event()) {
-    // Get the |x_root_window_| location out of the native event.
-    const gfx::Point x_root_location =
-        ui::EventSystemLocationFromNative(event->native_event());
-    if (DispatchHostWindowDragMovement(hittest, x_root_location))
-      event->StopPropagation();
-  }
-}
-
-void X11WindowEventFilter::LowerWindow() {
-  XLowerWindow(xdisplay_, xwindow_);
-}
-
-bool X11WindowEventFilter::DispatchHostWindowDragMovement(
-    int hittest,
-    const gfx::Point& screen_location) {
-  int direction = ui::HitTestToWmMoveResizeDirection(hittest);
-  if (direction == -1)
-    return false;
-
-  ui::DoWMMoveResize(xdisplay_, x_root_window_, xwindow_, screen_location,
-                     direction);
-  return true;
-}
-
-}  // namespace views

ui/views/widget/desktop_aura/x11_window_event_filter.h

-// 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.
-
-#ifndef UI_VIEWS_WIDGET_DESKTOP_AURA_X11_WINDOW_EVENT_FILTER_H_
-#define UI_VIEWS_WIDGET_DESKTOP_AURA_X11_WINDOW_EVENT_FILTER_H_
-
-#include "base/compiler_specific.h"
-#include "base/macros.h"
-#include "ui/events/event_handler.h"
-#include "ui/gfx/x/x11.h"
-#include "ui/gfx/x/x11_types.h"
-#include "ui/views/views_export.h"
-#include "ui/views/widget/desktop_aura/window_event_filter.h"
-
-namespace gfx {
-class Point;
-}
-
-namespace views {
-class DesktopWindowTreeHost;
-
-// An EventFilter that sets properties on X11 windows.
-class VIEWS_EXPORT X11WindowEventFilter : public WindowEventFilter {
- public:
-  explicit X11WindowEventFilter(DesktopWindowTreeHost* window_tree_host);
-  ~X11WindowEventFilter() override;
-
- private:
-  // WindowEventFilter override:
-  void MaybeDispatchHostWindowDragMovement(int hittest,
-                                           ui::MouseEvent* event) override;
-  void LowerWindow() override;
-
-  bool DispatchHostWindowDragMovement(int hittest,
-                                      const gfx::Point& screen_location);
-
-  // The display and the native X window hosting the root window.
-  XDisplay* xdisplay_;
-  ::Window xwindow_;
-
-  // The native root window.
-  ::Window x_root_window_;
-
-  DISALLOW_COPY_AND_ASSIGN(X11WindowEventFilter);
-};
-
-}  // namespace views
-
-#endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_X11_WINDOW_EVENT_FILTER_H_