Applied some post-SDL 2.0.0 fixes from SDL official repository.

Source/Android/src/org/libsdl/app/SDLActivity.java

@@ -709,11 +709,6 @@ class SDLSurface extends SurfaceView implements SurfaceHolder.Callback,
             SDLActivity.mSDLThread = new Thread(new SDLMain(), "SDLThread");
             enableSensor(Sensor.TYPE_ACCELEROMETER, true);
             SDLActivity.mSDLThread.start();
-        } else {
-            // The app already exists, we resume via handleResume
-            // Multiple sequential calls to surfaceChanged are handled internally by handleResume
-
-            SDLActivity.handleResume();
         }
     }
 

Source/ThirdParty/SDL/src/video/cocoa/SDL_cocoawindow.m

@@ -1052,9 +1052,11 @@ Cocoa_SetWindowFullscreen(_THIS, SDL_Window * window, SDL_VideoDisplay * display
         [nswindow setLevel:kCGNormalWindowLevel];
     }
 
-    [data->listener pauseVisibleObservation];
-    [nswindow makeKeyAndOrderFront:nil];
-    [data->listener resumeVisibleObservation];
+    if ([nswindow isVisible] || fullscreen) {
+        [data->listener pauseVisibleObservation];
+        [nswindow makeKeyAndOrderFront:nil];
+        [data->listener resumeVisibleObservation];
+    }
 
     ScheduleContextUpdates(data);