Web+: Use reference for urlcontext in app and window

It needs to be deleted after everything is done.
This seems to fix the crashes I could reproduce on exit in my VM.
So might fix #17583.
(WebView also has fContext, but I assume they are part of a window)

Change-Id: I0125f76b0b2331ac3b6a81d6c20087ebdedbf2f2
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5486
Reviewed-by: Fredrik Holmqvist <[email protected]>
Reviewed-by: Adrien Destugues <[email protected]>
Tested-by: Commit checker robot <[email protected]>

src/apps/webpositive/BrowserApp.cpp

@@ -125,7 +125,6 @@ BrowserApp::~BrowserApp()
 	delete fSettings;
 	delete fCookies;
 	delete fSession;
-	delete fContext;
 }
 
 

src/apps/webpositive/BrowserApp.h

@@ -80,7 +80,7 @@ private:
 			SettingsMessage*	fSettings;
 			SettingsMessage*	fCookies;
 			SettingsMessage*	fSession;
-			BPrivate::Network::BUrlContext*	fContext;
+			BReference<BPrivate::Network::BUrlContext>	fContext;
 
 			DownloadWindow*		fDownloadWindow;
 			SettingsWindow*		fSettingsWindow;

src/apps/webpositive/BrowserWindow.h

@@ -266,7 +266,7 @@ private:
 			bigtime_t			fLastMouseMovedTime;
 			BPoint				fLastMousePos;
 
-			BPrivate::Network::BUrlContext*	fContext;
+			BReference<BPrivate::Network::BUrlContext>	fContext;
 
 			// cached settings
 			SettingsMessage*	fAppSettings;