Simplify RadioNodeList's anonymous indexed getter
Simplify RadioNodeList's anonymous indexed getter

Make RadioNodeList's anonymous indexed getter argument mandatory and drop
the [IsIndex] IDL extended attribute. 'optional' and [IsIndex] have no
effect on the generated code of anonymous indexed getters:
- There is no way for the caller to omit the index
- The generated code uses ObjectTemplate::SetIndexedPropertyHandler() and
the IndexedPropertyGetterCallback takes a uint32_t in argument.

There is no web-exposed behavior change, the generated bindings code is
identical.

R=haraken
BUG=237739

Review URL: https://chromiumcodereview.appspot.com/21891009

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@155535 bbb929c8-8fbe-4397-9dbb-9b2b20218538

smishenk/blink-crosswalk,XiaosongWei/blink-crosswalk,modulexcite/blink,ondra-novak/blink,PeterWangIntel/blink-crosswalk,modulexcite/blink,XiaosongWei/blink-crosswalk,XiaosongWei/blink-crosswalk,Bysmyyr/blink-crosswalk,Pluto-tv/blink-crosswalk,smishenk/blink-crosswalk,PeterWangIntel/blink-crosswalk,XiaosongWei/blink-crosswalk,modulexcite/blink,ondra-novak/blink,smishenk/blink-crosswalk,crosswalk-project/blink-crosswalk-efl,modulexcite/blink,crosswalk-project/blink-crosswalk-efl,smishenk/blink-crosswalk,jtg-gg/blink,XiaosongWei/blink-crosswalk,nwjs/blink,crosswalk-project/blink-crosswalk-efl,XiaosongWei/blink-crosswalk,jtg-gg/blink,kurli/blink-crosswalk,Bysmyyr/blink-crosswalk,jtg-gg/blink,hgl888/blink-crosswalk-efl,jtg-gg/blink,nwjs/blink,jtg-gg/blink,kurli/blink-crosswalk,PeterWangIntel/blink-crosswalk,smishenk/blink-crosswalk,hgl888/blink-crosswalk-efl,PeterWangIntel/blink-crosswalk,kurli/blink-crosswalk,XiaosongWei/blink-crosswalk,PeterWangIntel/blink-crosswalk,Bysmyyr/blink-crosswalk,kurli/blink-crosswalk,ondra-novak/blink,nwjs/blink,hgl888/blink-crosswalk-efl,Pluto-tv/blink-crosswalk,kurli/blink-crosswalk,crosswalk-project/blink-crosswalk-efl,nwjs/blink,Pluto-tv/blink-crosswalk,modulexcite/blink,crosswalk-project/blink-crosswalk-efl,Bysmyyr/blink-crosswalk,nwjs/blink,smishenk/blink-crosswalk,crosswalk-project/blink-crosswalk-efl,hgl888/blink-crosswalk-efl,kurli/blink-crosswalk,crosswalk-project/blink-crosswalk-efl,jtg-gg/blink,Pluto-tv/blink-crosswalk,Bysmyyr/blink-crosswalk,nwjs/blink,XiaosongWei/blink-crosswalk,nwjs/blink,crosswalk-project/blink-crosswalk-efl,ondra-novak/blink,Pluto-tv/blink-crosswalk,jtg-gg/blink,PeterWangIntel/blink-crosswalk,Bysmyyr/blink-crosswalk,nwjs/blink,smishenk/blink-crosswalk,kurli/blink-crosswalk,hgl888/blink-crosswalk-efl,modulexcite/blink,jtg-gg/blink,smishenk/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,crosswalk-project/blink-crosswalk-efl,jtg-gg/blink,modulexcite/blink,Pluto-tv/blink-crosswalk,modulexcite/blink,ondra-novak/blink,smishenk/blink-crosswalk,ondra-novak/blink,XiaosongWei/blink-crosswalk,PeterWangIntel/blink-crosswalk,PeterWangIntel/blink-crosswalk,hgl888/blink-crosswalk-efl,hgl888/blink-crosswalk-efl,kurli/blink-crosswalk,kurli/blink-crosswalk,PeterWangIntel/blink-crosswalk,jtg-gg/blink,smishenk/blink-crosswalk,kurli/blink-crosswalk,PeterWangIntel/blink-crosswalk,hgl888/blink-crosswalk-efl,Pluto-tv/blink-crosswalk,modulexcite/blink,Bysmyyr/blink-crosswalk,Bysmyyr/blink-crosswalk,nwjs/blink,nwjs/blink,ondra-novak/blink,Bysmyyr/blink-crosswalk,ondra-novak/blink,modulexcite/blink,hgl888/blink-crosswalk-efl,hgl888/blink-crosswalk-efl,XiaosongWei/blink-crosswalk,Pluto-tv/blink-crosswalk,Bysmyyr/blink-crosswalk,ondra-novak/blink