Remove trailing commas from Blink IDLs

Source/bindings/tests/idls/TestPartialInterface.idl

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary formstrArg, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 11 matching lines @@
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR 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.
  */
 
 // This IDL file is for testing the bindings code generator and for tracking
 // changes in its ouput.
 [
-    Conditional=Condition11|Condition12,
+    Conditional=Condition11|Condition12
 ] partial interface TestInterface {
     static readonly attribute long supplementalStaticReadOnlyAttr;
     static attribute DOMString supplementalStaticAttr;
     readonly attribute DOMString supplementalStr1;
     attribute DOMString supplementalStr2;
     [CustomGetter, CustomSetter] attribute DOMString supplementalStr3;
     attribute Node supplementalNode;
 
     void supplementalMethod1();
     [CallWith=ScriptExecutionContext, RaisesException] TestObject supplementalMethod2(DOMString strArg, TestObject objArg);
     [Custom] void supplementalMethod3();
     static void supplementalMethod4();
 
     const unsigned short SUPPLEMENTALCONSTANT1 = 1;
     [Reflect=CONST_IMPL] const unsigned short SUPPLEMENTALCONSTANT2 = 2;
 
     [EnabledAtRuntime=condition13] attribute Node Node13;
     [EnabledPerContext=condition14] attribute Node Node14;
     [EnabledAtRuntime=condition15, EnabledPerContext=condition16] attribute Node Node15;
 
 };