Delete pointless GRAB_SERVER_DURING_CONTEXT macro

Summary: One could just use XServerGrabber class directly.

Test Plan: Compiles.

Reviewers: #kwin, romangg

Reviewed By: #kwin, romangg

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D24119

unmanaged.cpp

@@ -56,7 +56,7 @@ Unmanaged::~Unmanaged()
 
 bool Unmanaged::track(xcb_window_t w)
 {
-    GRAB_SERVER_DURING_CONTEXT
+    XServerGrabber xserverGrabber;
     Xcb::WindowAttributes attr(w);
     Xcb::WindowGeometry geo(w);
     if (attr.isNull() || attr->map_state != XCB_MAP_STATE_VIEWABLE) {

utils.h

@@ -151,8 +151,6 @@ void KWIN_EXPORT ungrabXKeyboard();
  * Small helper class which performs grabXServer in the ctor and
  * ungrabXServer in the dtor. Use this class to ensure that grab and
  * ungrab are matched.
- *
- * To simplify usage consider using the macro GRAB_SERVER_DURING_CONTEXT
  */
 class XServerGrabber
 {
@@ -165,8 +163,6 @@ public:
     }
 };
 
-#define GRAB_SERVER_DURING_CONTEXT XServerGrabber xserverGrabber;
-
 // the docs say it's UrgencyHint, but it's often #defined as XUrgencyHint
 #ifndef UrgencyHint
 #define UrgencyHint XUrgencyHint