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

Source/modules/encryptedmedia/MediaKeyNeededEvent.idl

Index: Source/modules/encryptedmedia/MediaKeyNeededEvent.idl
diff --git a/Source/modules/encryptedmedia/MediaKeyNeededEvent.idl b/Source/modules/encryptedmedia/MediaKeyNeededEvent.idl
index 0c1b42b2e4d84f4c08dc0ff26b5cba71c4663c6c..82f72f83b1f0369b4ad3e2a0ff38bb39955a8ca0 100644
--- a/Source/modules/encryptedmedia/MediaKeyNeededEvent.idl
+++ b/Source/modules/encryptedmedia/MediaKeyNeededEvent.idl
@@ -20,13 +20,13 @@
  * 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.
  */
 
 [
     Conditional=ENCRYPTED_MEDIA_V2,
     EnabledAtRuntime=encryptedMedia,
-    ConstructorTemplate=Event 
+    ConstructorTemplate=Event
 ] interface MediaKeyNeededEvent : Event {
     readonly attribute Uint8Array initData;
 };