Fix compilation against latest GTK3 changes

With the newest changes to GTK3, some things were changed. This patch
now uses the features introduced in gtk3-compat.h in previous patches.

This patch also introduces a macro named USE_GTK3 that is used to
differentiate between GTK3 and GTK2. Its main use is differenting
between expose and draw handlers for GtkWidget subclasses.

The draw vs expose handlers question is usually handled by using ifdefs
at the beginning and end to set up/tear down a cairo_t and then use it.

However, when the function is too different and too many ifdefs would be
necessary, two versions of the function are written. This is currently
the case for:
- MetaAccelLabel
- MetaFrames

https://bugzilla.gnome.org/show_bug.cgi?id=630203

src/ui/frames.c

@@ -40,6 +40,8 @@
 #include "gtk-compat.h"
 #include "gdk-compat.h"
 
+#include <cairo-xlib.h>
+
 #ifdef HAVE_SHAPE
 #include <X11/extensions/shape.h>
 #endif
@@ -64,8 +66,13 @@ static gboolean meta_frames_motion_notify_event   (GtkWidget           *widget,
                                                    GdkEventMotion      *event);
 static gboolean meta_frames_destroy_event         (GtkWidget           *widget,
                                                    GdkEventAny         *event);
+#ifdef USE_GTK3
+static gboolean meta_frames_draw                  (GtkWidget           *widget,
+                                                   cairo_t             *cr);
+#else
 static gboolean meta_frames_expose_event          (GtkWidget           *widget,
                                                    GdkEventExpose      *event);
+#endif
 static gboolean meta_frames_enter_notify_event    (GtkWidget           *widget,
                                                    GdkEventCrossing    *event);
 static gboolean meta_frames_leave_notify_event    (GtkWidget           *widget,
@@ -148,7 +155,11 @@ meta_frames_class_init (MetaFramesClass *class)
   widget_class->map = meta_frames_map;
   widget_class->unmap = meta_frames_unmap;
   
+#ifdef USE_GTK3
+  widget_class->draw = meta_frames_draw;
+#else
   widget_class->expose_event = meta_frames_expose_event;
+#endif
   widget_class->destroy_event = meta_frames_destroy_event;  
   widget_class->button_press_event = meta_frames_button_press_event;
   widget_class->button_release_event = meta_frames_button_release_event;
@@ -1016,7 +1027,8 @@ meta_frames_move_resize_frame (MetaFrames *frames,
   MetaUIFrame *frame = meta_frames_lookup_window (frames, xwindow);
   int old_width, old_height;
   
-  gdk_drawable_get_size (frame->window, &old_width, &old_height);
+  old_width = gdk_window_get_width (frame->window);
+  old_height = gdk_window_get_height (frame->window);
 
   gdk_window_move_resize (frame->window, x, y, width, height);
 
@@ -2278,6 +2290,72 @@ cached_pixels_draw (CachedPixels *pixels,
     }
 }
 
+#ifdef USE_GTK3
+static gboolean
+meta_frames_draw (GtkWidget *widget,
+                  cairo_t   *cr)
+{
+  MetaUIFrame *frame;
+  MetaFrames *frames;
+  CachedPixels *pixels;
+  MetaRegion *region;
+  GdkRectangle *areas, clip;
+  int i, n_areas;
+  cairo_surface_t *target;
+
+  frames = META_FRAMES (widget);
+  target = cairo_get_target (cr);
+  gdk_cairo_get_clip_rectangle (cr, &clip);
+
+  g_assert (cairo_surface_get_type (target) == CAIRO_SURFACE_TYPE_XLIB);
+  frame = meta_frames_lookup_window (frames, cairo_xlib_surface_get_drawable (target));
+  if (frame == NULL)
+    return FALSE;
+
+  if (frames->expose_delay_count > 0)
+    {
+      /* Redraw this entire frame later */
+      frame->expose_delayed = TRUE;
+      return TRUE;
+    }
+
+  populate_cache (frames, frame);
+
+  region = meta_region_new_from_rectangle (&clip);
+  
+  pixels = get_cache (frames, frame);
+
+  cached_pixels_draw (pixels, cr, region);
+  
+  clip_to_screen (region, frame);
+  subtract_client_area (region, frame);
+
+  meta_region_get_rectangles (region, &areas, &n_areas);
+
+  for (i = 0; i < n_areas; i++)
+    {
+      cairo_save (cr);
+
+      gdk_cairo_rectangle (cr, &areas[i]);
+      cairo_clip (cr);
+
+      cairo_push_group (cr);
+
+      meta_frames_paint (frames, frame, cr, 0, 0);
+
+      cairo_pop_group_to_source (cr);
+      cairo_paint (cr);
+
+      cairo_restore (cr);
+    }
+
+  g_free (areas);
+
+  meta_region_destroy (region);
+  
+  return TRUE;
+}
+#else /* !USE_GTK3 */
 static gboolean
 meta_frames_expose_event (GtkWidget           *widget,
                           GdkEventExpose      *event)
@@ -2341,6 +2419,7 @@ meta_frames_expose_event (GtkWidget           *widget,
   
   return TRUE;
 }
+#endif /* !USE_GTK3 */
 
 static void
 meta_frames_paint (MetaFrames   *frames,