Fix trailing whitespace in .cpp, .h, and .idl files

Source/core/dom/DocumentEventQueue.h

Index: Source/core/dom/DocumentEventQueue.h
diff --git a/Source/core/dom/DocumentEventQueue.h b/Source/core/dom/DocumentEventQueue.h
index 84d663e9d3cec4e16b0313ffc5d98e7ba79c2377..bd8fb76c65adbc9397cbd26e6d6cf6f8eb347b35 100644
--- a/Source/core/dom/DocumentEventQueue.h
+++ b/Source/core/dom/DocumentEventQueue.h
@@ -20,7 +20,7 @@
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  */
 
@@ -69,7 +69,7 @@ private:
     HashSet<Node*> m_nodesWithQueuedScrollEvents;
     bool m_isClosed;
 
-    friend class DocumentEventQueueTimer;    
+    friend class DocumentEventQueueTimer;
 };
 
 }