Clean up some remaining obsolete coordinate-space naming.

third_party/WebKit/public/web/WebInputEvent.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 303 matching lines @@
 
     // Sets keyIdentifier based on the value of windowsKeyCode.  This is
     // handy for generating synthetic keyboard events.
     BLINK_EXPORT void setKeyIdentifierFromWindowsKeyCode();
 };
 
 // WebMouseEvent --------------------------------------------------------------
 
 class WebMouseEvent : public WebInputEvent, public WebPointerProperties {
 public:
-    // Window coordinate
+    // Renderer coordinates. Similar to viewport coordinates but without
+    // DevTools emulation transform or overscroll applied. i.e. the coordinates
+    // in Chromium's RenderView bounds.
     int x;
     int y;
 
     // DEPRECATED (crbug.com/507787)
     int windowX;
     int windowY;
 
     // Screen coordinate
     int globalX;
     int globalY;
@@ skipping 253 matching lines @@
         , uniqueTouchEventId(0)
     {
     }
 };
 
 #pragma pack(pop)
 
 } // namespace blink
 
 #endif