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

Source/core/editing/MergeIdenticalElementsCommand.h

Index: Source/core/editing/MergeIdenticalElementsCommand.h
diff --git a/Source/core/editing/MergeIdenticalElementsCommand.h b/Source/core/editing/MergeIdenticalElementsCommand.h
index f9fab99a3a65ddfa7818d586aa422affe9fcd19f..0b1003d12fb053cf107da35d369aa02054275937 100644
--- a/Source/core/editing/MergeIdenticalElementsCommand.h
+++ b/Source/core/editing/MergeIdenticalElementsCommand.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.
  */
 
 #ifndef MergeIdenticalElementsCommand_h
@@ -42,11 +42,11 @@ private:
 
     virtual void doApply() OVERRIDE;
     virtual void doUnapply() OVERRIDE;
-    
+
 #ifndef NDEBUG
     virtual void getNodesInCommand(HashSet<Node*>&) OVERRIDE;
 #endif
-    
+
     RefPtr<Element> m_element1;
     RefPtr<Element> m_element2;
     RefPtr<Node> m_atChild;