Fix trailing whitespace in .cpp, .h, and .idl files (ex. Source/core)

public/web/WebFileWriter.h

 /*
  * Copyright (C) 2010 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 33 matching lines @@
 
     // Only one write or one truncate operation can be in progress at a time.
     // These functions are asynchronous and will report results through the WebFileWriter's associated WebFileWriterClient.
     virtual void write(long long position, const WebURL& blobURL) = 0;
     virtual void truncate(long long length) = 0;
 
     // Cancel will attempt to abort a running write or truncate.  However, it may not be possible to cancel an in-progress action, or the call may have come in too late.  Partial writes are possible.
     // Do not call cancel when there is no write or truncate in progress.
     virtual void cancel() = 0;
 };
-    
+
 } // namespace WebKit
 
 #endif