Fixed a large client side memory leak for app_server memory.

* The areas allocated for BBitmaps were never deleted, even though the
  app_server deleted its part when the memory got freed.
* This resulted in a constant memory increase if the application in question
  would operate on many changing large bitmaps, like photos.
* Since the bitmaps are reference counted, we don't actually know when to delete
  the areas, so that the app_server now notifies the client whenever that is
  possible.
* This might fix #6824.

src/kits/app/Application.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright 2001-2009, Haiku.
+ * Copyright 2001-2012, Haiku.
  * Distributed under the terms of the MIT License.
  *
  * Authors:
@@ -601,9 +601,18 @@ BApplication::MessageReceived(BMessage *message)
 			break;
 
 		case kMsgAppServerRestarted:
-		{
 			_ReconnectToServer();
 			break;
+
+		case kMsgDeleteServerMemoryArea:
+		{
+			int32 serverArea;
+			if (message->FindInt32("server area", &serverArea) == B_OK) {
+				// The link is not used, but we currently borrow its lock
+				BPrivate::AppServerLink link;
+				fServerAllocator->RemoveArea(serverArea);
+			}
+			break;
 		}
 
 		default: