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

Source/wtf/MainThread.h

Index: Source/wtf/MainThread.h
diff --git a/Source/wtf/MainThread.h b/Source/wtf/MainThread.h
index f9db1e2e662f96489cd7d19c952ef333c2c4c70e..7e1aaa8613769d7cc541858cc7d8cd1aa98bc005 100644
--- a/Source/wtf/MainThread.h
+++ b/Source/wtf/MainThread.h
@@ -7,13 +7,13 @@
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
- *     notice, this list of conditions and the following disclaimer. 
+ *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
- *     documentation and/or other materials provided with the distribution. 
+ *     documentation and/or other materials provided with the distribution.
  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  *     its contributors may be used to endorse or promote products derived
- *     from this software without specific prior written permission. 
+ *     from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
@@ -46,7 +46,7 @@ WTF_EXPORT void callOnMainThread(MainThreadFunction*, void* context);
 
 template<typename> class Function;
 WTF_EXPORT void callOnMainThread(const Function<void ()>&);
-    
+
 WTF_EXPORT bool isMainThread();
 
 } // namespace WTF