util: Add a SCREEN_CAST debug topic

This is going to be useful to log dropped frames and other more common
errors about screencasting.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1709>

src/core/main.c

@@ -121,6 +121,7 @@ static const GDebugKey meta_debug_keys[] = {
   { "input", META_DEBUG_INPUT },
   { "wayland", META_DEBUG_WAYLAND },
   { "kms", META_DEBUG_KMS },
+  { "screen-cast", META_DEBUG_SCREEN_CAST },
 };
 
 /*

src/core/util.c

@@ -278,6 +278,8 @@ topic_name (MetaDebugTopic topic)
       return "INPUT";
     case META_DEBUG_KMS:
       return "KMS";
+    case META_DEBUG_SCREEN_CAST:
+      return "SCREEN_CAST";
     case META_DEBUG_VERBOSE:
       return "VERBOSE";
     case META_DEBUG_WAYLAND:

src/meta/util.h

@@ -77,6 +77,7 @@ void meta_fatal      (const char *format,
  * @META_DEBUG_EDGE_RESISTANCE: edge resistance
  * @META_DEBUG_WAYLAND: Wayland
  * @META_DEBUG_KMS: kernel mode setting
+ * @META_DEBUG_SCREEN_CAST: screencasting
  */
 typedef enum
 {
@@ -103,6 +104,7 @@ typedef enum
   META_DEBUG_INPUT           = 1 << 19,
   META_DEBUG_WAYLAND         = 1 << 20,
   META_DEBUG_KMS             = 1 << 21,
+  META_DEBUG_SCREEN_CAST     = 1 << 22,
 } MetaDebugTopic;
 
 /**