exo: Fix dragging edge cases

components/exo/wayland/server.cc

Index: components/exo/wayland/server.cc
diff --git a/components/exo/wayland/server.cc b/components/exo/wayland/server.cc
index 53b20f9432e12933ea581195d6beb1b66a0a4470..e267dee66179e411cf9ad4ff61a562f0a7695429 100644
--- a/components/exo/wayland/server.cc
+++ b/components/exo/wayland/server.cc
@@ -1535,6 +1535,14 @@ void remote_surface_unset_system_modal(wl_client* client,
   GetUserDataAs<ShellSurface>(resource)->SetSystemModal(false);
 }
 
+void remote_surface_set_moving(wl_client* client, wl_resource* resource) {
+  GetUserDataAs<ShellSurface>(resource)->SetMoving();
+}
+
+void remote_surface_unset_moving(wl_client* client, wl_resource* resource) {
+  GetUserDataAs<ShellSurface>(resource)->UnsetMoving(false /* revert */);
+}
+
 const struct zcr_remote_surface_v1_interface remote_surface_implementation = {
     remote_surface_destroy,
     remote_surface_set_app_id,
@@ -1553,7 +1561,9 @@ const struct zcr_remote_surface_v1_interface remote_surface_implementation = {
     remote_surface_pin,
     remote_surface_unpin,
     remote_surface_set_system_modal,
-    remote_surface_unset_system_modal};
+    remote_surface_unset_system_modal,
+    remote_surface_set_moving,
+    remote_surface_unset_moving};
 
 ////////////////////////////////////////////////////////////////////////////////
 // notification_surface_interface:
@@ -1570,7 +1580,7 @@ const struct zcr_notification_surface_v1_interface
 
 // Implements remote shell interface and monitors workspace state needed
 // for the remote shell interface.
-class WaylandRemoteShell : public WMHelper::MaximizeModeObserver,
+class WaylandRemoteShell : public WMHelper::ShellObserver,
                            public WMHelper::ActivationObserver,
                            public display::DisplayObserver {
  public:
@@ -1579,7 +1589,7 @@ class WaylandRemoteShell : public WMHelper::MaximizeModeObserver,
         remote_shell_resource_(remote_shell_resource),
         weak_ptr_factory_(this) {
     auto* helper = WMHelper::GetInstance();
-    helper->AddMaximizeModeObserver(this);
+    helper->AddShellObserver(this);
     helper->AddActivationObserver(this);
     display::Screen::GetScreen()->AddObserver(this);
 
@@ -1587,12 +1597,12 @@ class WaylandRemoteShell : public WMHelper::MaximizeModeObserver,
                        ? ZCR_REMOTE_SHELL_V1_LAYOUT_MODE_TABLET
                        : ZCR_REMOTE_SHELL_V1_LAYOUT_MODE_WINDOWED;
 
-    SendPrimaryDisplayMetrics();
+    SendDisplayMetrics();
     SendActivated(helper->GetActiveWindow(), nullptr);
   }
   ~WaylandRemoteShell() override {
     auto* helper = WMHelper::GetInstance();
-    helper->RemoveMaximizeModeObserver(this);
+    helper->RemoveShellObserver(this);
     helper->RemoveActivationObserver(this);
     display::Screen::GetScreen()->RemoveObserver(this);
   }
@@ -1609,40 +1619,40 @@ class WaylandRemoteShell : public WMHelper::MaximizeModeObserver,
   }
 
   // Overridden from display::DisplayObserver:
-  void OnDisplayAdded(const display::Display& new_display) override {}
-  void OnDisplayRemoved(const display::Display& new_display) override {}
+  void OnDisplayAdded(const display::Display& new_display) override {
+    if (IsMultiDisplaySupported())
+      ScheduleSendDisplayMetrics();
+  }
+
+  void OnDisplayRemoved(const display::Display& new_display) override {
+    if (IsMultiDisplaySupported())
+      ScheduleSendDisplayMetrics();
+  }
+
   void OnDisplayMetricsChanged(const display::Display& display,
                                uint32_t changed_metrics) override {
-    if (display::Screen::GetScreen()->GetPrimaryDisplay().id() != display.id())
+    if (!IsMultiDisplaySupported() &&
+        display::Screen::GetScreen()->GetPrimaryDisplay().id() != display.id())
       return;
 
-    // No need to update when a primary dislpay has changed without bounds
+    // No need to update when a primary display has changed without bounds
     // change. See WaylandPrimaryDisplayObserver::OnDisplayMetricsChanged
     // for more details.
     if (changed_metrics &
         (DISPLAY_METRIC_BOUNDS | DISPLAY_METRIC_DEVICE_SCALE_FACTOR |
          DISPLAY_METRIC_ROTATION | DISPLAY_METRIC_WORK_AREA)) {
-      SendDisplayMetrics(display);
+      ScheduleSendDisplayMetrics();
     }
   }
 
-  // Overridden from WMHelper::MaximizeModeObserver:
+  // Overridden from WMHelper::ShellObserver:
   void OnMaximizeModeStarted() override {
     layout_mode_ = ZCR_REMOTE_SHELL_V1_LAYOUT_MODE_TABLET;
-
-    send_configure_after_layout_change_ = true;
-    base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
-        FROM_HERE, base::Bind(&WaylandRemoteShell::MaybeSendConfigure,
-                              weak_ptr_factory_.GetWeakPtr()),
-        base::TimeDelta::FromMilliseconds(kConfigureDelayAfterLayoutSwitchMs));
+    ScheduleSendDisplayMetrics(kConfigureDelayAfterLayoutSwitchMs);
   }
   void OnMaximizeModeEnded() override {
     layout_mode_ = ZCR_REMOTE_SHELL_V1_LAYOUT_MODE_WINDOWED;
-    send_configure_after_layout_change_ = true;
-    base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
-        FROM_HERE, base::Bind(&WaylandRemoteShell::MaybeSendConfigure,
-                              weak_ptr_factory_.GetWeakPtr()),
-        base::TimeDelta::FromMilliseconds(kConfigureDelayAfterLayoutSwitchMs));
+    ScheduleSendDisplayMetrics(kConfigureDelayAfterLayoutSwitchMs);
   }
 
   // Overridden from WMHelper::ActivationObserver:
@@ -1652,27 +1662,46 @@ class WaylandRemoteShell : public WMHelper::MaximizeModeObserver,
   }
 
  private:
-  void SendPrimaryDisplayMetrics() {
-    const display::Display primary =
-        display::Screen::GetScreen()->GetPrimaryDisplay();
-
-    SendDisplayMetrics(primary);
+  bool IsMultiDisplaySupported() const {
+    return wl_resource_get_version(remote_shell_resource_) >= 2;
   }
 
-  void MaybeSendConfigure() {
-    if (send_configure_after_layout_change_)
-      SendPrimaryDisplayMetrics();
+  void ScheduleSendDisplayMetrics(int delay_ms = 0) {
+    needs_send_display_metrics_ = true;
+    base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
+        FROM_HERE, base::Bind(&WaylandRemoteShell::SendDisplayMetrics,
+                              weak_ptr_factory_.GetWeakPtr()),
+        base::TimeDelta::FromMilliseconds(delay_ms));
   }
 
-  void SendDisplayMetrics(const display::Display& display) {
-    send_configure_after_layout_change_ = false;
+  void SendDisplayMetrics() {
+    if (!needs_send_display_metrics_)
+      return;
+    needs_send_display_metrics_ = false;
+
+    const display::Screen* screen = display::Screen::GetScreen();
+    const display::Display primary = screen->GetPrimaryDisplay();
+
+    gfx::Size size = primary.size();
+
+    if (IsMultiDisplaySupported()) {
+      // Virtual screen is the bounding box of the displays in screen
+      // coordinates.
+      gfx::Rect bounds;
+      for (const auto& display : screen->GetAllDisplays())
+        bounds.Union(display.bounds());
+
+      display_->set_virtual_origin(bounds.origin());
+      size = bounds.size();
+    }
 
-    const gfx::Insets& work_area_insets = display.GetWorkAreaInsets();
+    // TODO(domlaskowski): Send insets for each workspace.
+    const gfx::Insets& work_area_insets = primary.GetWorkAreaInsets();
 
     zcr_remote_shell_v1_send_configuration_changed(
-        remote_shell_resource_, display.size().width(), display.size().height(),
-        OutputTransform(display.rotation()),
-        wl_fixed_from_double(display.device_scale_factor()),
+        remote_shell_resource_, size.width(), size.height(),
+        OutputTransform(primary.rotation()),
+        wl_fixed_from_double(primary.device_scale_factor()),
         work_area_insets.left(), work_area_insets.top(),
         work_area_insets.right(), work_area_insets.bottom(), layout_mode_);
     wl_client_flush(wl_resource_get_client(remote_shell_resource_));
@@ -1717,7 +1746,7 @@ class WaylandRemoteShell : public WMHelper::MaximizeModeObserver,
   // The remote shell resource associated with observer.
   wl_resource* const remote_shell_resource_;
 
-  bool send_configure_after_layout_change_ = false;
+  bool needs_send_display_metrics_ = true;
 
   int layout_mode_ = ZCR_REMOTE_SHELL_V1_LAYOUT_MODE_WINDOWED;
 
@@ -1840,7 +1869,7 @@ const struct zcr_remote_shell_v1_interface remote_shell_implementation = {
     remote_shell_destroy, remote_shell_get_remote_surface,
     remote_shell_get_notification_surface};
 
-const uint32_t remote_shell_version = 1;
+const uint32_t remote_shell_version = 2;
 
 void bind_remote_shell(wl_client* client,
                        void* data,