Linux Aura: Use managed tab dragging when possible (Reland)

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
index 816faa3f312f4ef52ff418a99b5e3d7016ac760c..8401b4a9445fab2ff8e714509e15c6a51fdc1d29 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
@@ -60,6 +60,7 @@
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host_observer_x11.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_desktop_window_move_client_managed.h"
 #include "ui/views/widget/desktop_aura/x11_pointer_grab.h"
 #include "ui/views/widget/desktop_aura/x11_window_event_filter.h"
 #include "ui/wm/core/compound_event_filter.h"
@@ -89,52 +90,51 @@ const int k_NET_WM_STATE_REMOVE = 0;
 // should appear on all desktops.
 const int kAllDesktops = 0xFFFFFFFF;
 
-const char* kAtomsToCache[] = {
-  "UTF8_STRING",
-  "WM_DELETE_WINDOW",
-  "WM_PROTOCOLS",
-  "_NET_ACTIVE_WINDOW",
-  "_NET_FRAME_EXTENTS",
-  "_NET_WM_CM_S0",
-  "_NET_WM_DESKTOP",
-  "_NET_WM_ICON",
-  "_NET_WM_NAME",
-  "_NET_WM_PID",
-  "_NET_WM_PING",
-  "_NET_WM_STATE",
-  "_NET_WM_STATE_ABOVE",
-  "_NET_WM_STATE_FULLSCREEN",
-  "_NET_WM_STATE_HIDDEN",
-  "_NET_WM_STATE_MAXIMIZED_HORZ",
-  "_NET_WM_STATE_MAXIMIZED_VERT",
-  "_NET_WM_STATE_SKIP_TASKBAR",
-  "_NET_WM_STATE_STICKY",
-  "_NET_WM_USER_TIME",
-  "_NET_WM_WINDOW_OPACITY",
-  "_NET_WM_WINDOW_TYPE",
-  "_NET_WM_WINDOW_TYPE_DND",
-  "_NET_WM_WINDOW_TYPE_MENU",
-  "_NET_WM_WINDOW_TYPE_NORMAL",
-  "_NET_WM_WINDOW_TYPE_NOTIFICATION",
-  "_NET_WM_WINDOW_TYPE_TOOLTIP",
-  "XdndActionAsk",
-  "XdndActionCopy",
-  "XdndActionLink",
-  "XdndActionList",
-  "XdndActionMove",
-  "XdndActionPrivate",
-  "XdndAware",
-  "XdndDrop",
-  "XdndEnter",
-  "XdndFinished",
-  "XdndLeave",
-  "XdndPosition",
-  "XdndProxy",  // Proxy windows?
-  "XdndSelection",
-  "XdndStatus",
-  "XdndTypeList",
-  NULL
-};
+const char* kAtomsToCache[] = {"UTF8_STRING",
+                               "WM_DELETE_WINDOW",
+                               "WM_PROTOCOLS",
+                               "_NET_ACTIVE_WINDOW",
+                               "_NET_FRAME_EXTENTS",
+                               "_NET_WM_CM_S0",
+                               "_NET_WM_DESKTOP",
+                               "_NET_WM_ICON",
+                               "_NET_WM_MOVERESIZE",
+                               "_NET_WM_NAME",
+                               "_NET_WM_PID",
+                               "_NET_WM_PING",
+                               "_NET_WM_STATE",
+                               "_NET_WM_STATE_ABOVE",
+                               "_NET_WM_STATE_FULLSCREEN",
+                               "_NET_WM_STATE_HIDDEN",
+                               "_NET_WM_STATE_MAXIMIZED_HORZ",
+                               "_NET_WM_STATE_MAXIMIZED_VERT",
+                               "_NET_WM_STATE_SKIP_TASKBAR",
+                               "_NET_WM_STATE_STICKY",
+                               "_NET_WM_USER_TIME",
+                               "_NET_WM_WINDOW_OPACITY",
+                               "_NET_WM_WINDOW_TYPE",
+                               "_NET_WM_WINDOW_TYPE_DND",
+                               "_NET_WM_WINDOW_TYPE_MENU",
+                               "_NET_WM_WINDOW_TYPE_NORMAL",
+                               "_NET_WM_WINDOW_TYPE_NOTIFICATION",
+                               "_NET_WM_WINDOW_TYPE_TOOLTIP",
+                               "XdndActionAsk",
+                               "XdndActionCopy",
+                               "XdndActionLink",
+                               "XdndActionList",
+                               "XdndActionMove",
+                               "XdndActionPrivate",
+                               "XdndAware",
+                               "XdndDrop",
+                               "XdndEnter",
+                               "XdndFinished",
+                               "XdndLeave",
+                               "XdndPosition",
+                               "XdndProxy",  // Proxy windows?
+                               "XdndSelection",
+                               "XdndStatus",
+                               "XdndTypeList",
+                               NULL};
 
 const char kX11WindowRolePopup[] = "popup";
 const char kX11WindowRoleBubble[] = "bubble";
@@ -176,6 +176,27 @@ int XI2ModeToXMode(int xi2_mode) {
   }
 }
 
+bool CanUseManagedWindowMove() {
+  if (!ui::IsXInput2Available() ||
+      !ui::WmSupportsHint(ui::GetAtom("_NET_WM_MOVERESIZE")))
+    return false;
+  switch(ui::GuessWindowManager()) {
+    case ui::WM_COMPIZ:
+    case ui::WM_METACITY:
+    case ui::WM_MUFFIN:
+    case ui::WM_MUTTER:
+      return true;
+    case ui::WM_XFWM4:
+      // Xfwm does not release the pointer grab when the dragging window gets
+      // destroyed (dragged into another window), and does not support
+      // _NET_WM_MOVERESIZE_CANCEL.
+      return false;
+    default:
+      // Whitelist only tested WMs.
+      return false;
+  }
+}
+
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -471,7 +492,12 @@ void DesktopWindowTreeHostX11::OnNativeWidgetCreated(
   SetUseNativeFrame(params.type == Widget::InitParams::TYPE_WINDOW &&
                     !params.remove_standard_frame);
 
-  x11_window_move_client_.reset(new X11DesktopWindowMoveClient);
+
+  static bool can_use_managed_move = CanUseManagedWindowMove();
+  if (can_use_managed_move && is_managed_)
+    x11_window_move_client_.reset(new X11DesktopWindowMoveClientManaged);
+  else
+    x11_window_move_client_.reset(new X11DesktopWindowMoveClient);
   aura::client::SetWindowMoveClient(window(), x11_window_move_client_.get());
 
   SetWindowTransparency();
@@ -1359,6 +1385,7 @@ void DesktopWindowTreeHostX11::InitX11Window(
   if (!activatable_)
     swa.override_redirect = True;
 
+  is_managed_ = !swa.override_redirect;
   if (swa.override_redirect)
     attribute_mask |= CWOverrideRedirect;