Flip screen coordinates when converting NSEvent to WebMouseEvent. Enable proc...

webkit/api/src/mac/WebInputEventFactory.mm

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2006-2009 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 949 matching lines @@
     case NSRightMouseDragged:
         result.type = WebInputEvent::MouseMove;
         result.button = WebMouseEvent::ButtonRight;
         break;
     default:
         ASSERT_NOT_REACHED();
     }
 
     NSPoint location = [NSEvent mouseLocation];  // global coordinates
     result.globalX = location.x;
-    result.globalY = location.y;
+    result.globalY = [[[view window] screen] frame].size.height - location.y;
 
     NSPoint windowLocal = [event locationInWindow];
     location = [view convertPoint:windowLocal fromView:nil];
     result.y = [view frame].size.height - location.y;  // flip y
     result.x = location.x;
     result.windowX = result.x;
     result.windowY = result.y;
 
     result.modifiers = modifiersFromEvent(event);
 
@@ skipping 150 matching lines @@
         result.deltaX = [event deltaX] * scrollbarPixelsPerCocoaTick;
         result.deltaY = [event deltaY] * scrollbarPixelsPerCocoaTick;
     }
 
     result.timeStampSeconds = [event timestamp];
 
     return result;
 }
 
 } // namespace WebKit