macosx: robustify media key trap handling

Only start and stop media key support when needed (ressource-intensive).

(cherry picked from commit 272b0ffa072918603894ecbb22e037824f1dbcfa)
Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>

modules/gui/macosx/intf.h

@@ -105,6 +105,7 @@ static NSString * VLCInputChangedNotification = @"VLCInputChangedNotification";
     BOOL b_mediaKeySupport;
     BOOL b_mediakeyJustJumped;
     SPMediaKeyTap * o_mediaKeyController;
+    BOOL b_mediaKeyTrapEnabled;
 
     NSArray *o_usedHotkeys;
 

modules/gui/macosx/intf.m

@@ -1833,18 +1833,23 @@ static const int kCurrentPreferencesVersion = 3;
 - (void)coreChangedMediaKeySupportSetting: (NSNotification *)o_notification
 {
     b_mediaKeySupport = var_InheritBool(VLCIntf, "macosx-mediakeys");
-    if (b_mediaKeySupport) {
-        if (!o_mediaKeyController)
-            o_mediaKeyController = [[SPMediaKeyTap alloc] initWithDelegate:self];
+    if (b_mediaKeySupport && !o_mediaKeyController)
+        o_mediaKeyController = [[SPMediaKeyTap alloc] initWithDelegate:self];
 
-        if ([[[VLCMain sharedInstance] playlist] currentPlaylistRoot]->i_children > 0 ||
-            p_current_input)
+    if (b_mediaKeySupport && ([[[VLCMain sharedInstance] playlist] currentPlaylistRoot]->i_children > 0 ||
+                              p_current_input)) {
+        if (!b_mediaKeyTrapEnabled) {
+            b_mediaKeyTrapEnabled = YES;
+            msg_Dbg(p_intf, "Enable media key support");
             [o_mediaKeyController startWatchingMediaKeys];
-        else
+        }
+    } else {
+        if (b_mediaKeyTrapEnabled) {
+            b_mediaKeyTrapEnabled = NO;
+            msg_Dbg(p_intf, "Disable media key support");
             [o_mediaKeyController stopWatchingMediaKeys];
+        }
     }
-    else if (!b_mediaKeySupport && o_mediaKeyController)
-        [o_mediaKeyController stopWatchingMediaKeys];
 }
 
 @end

modules/gui/macosx/simple_prefs.m

@@ -1451,10 +1451,6 @@ static inline void save_string_list(intf_thread_t * p_intf, id object, const cha
         [o_hotkeys_listbox reloadData];
         b_hotkeyChanged = YES;
     }
-
-    [[NSNotificationCenter defaultCenter] postNotificationName: @"VLCMediaKeySupportSettingChanged"
-                                                        object: nil
-                                                      userInfo: nil];
 }
 
 - (void)showHotkeySettings