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

Source/modules/encryptedmedia/MediaKeySession.idl

Index: Source/modules/encryptedmedia/MediaKeySession.idl
diff --git a/Source/modules/encryptedmedia/MediaKeySession.idl b/Source/modules/encryptedmedia/MediaKeySession.idl
index 3afc689f8881d3d526838bec43fcdaae266da7e1..a353455b6ad50e3d54e3f8d5f40d9ed24b73f90a 100644
--- a/Source/modules/encryptedmedia/MediaKeySession.idl
+++ b/Source/modules/encryptedmedia/MediaKeySession.idl
@@ -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.
      */
 
 [
@@ -37,7 +37,7 @@
     // session operations
     [RaisesException] void update(Uint8Array key);
     void close();
-    
+
     // EventListeners
     [EnabledAtRuntime=encryptedMedia] attribute EventListener onwebkitkeyadded;
     [EnabledAtRuntime=encryptedMedia] attribute EventListener onwebkitkeyerror;