json_schema_compiler: make util::AddItemToList take a const reference to match the compiler.
json_schema_compiler: make util::AddItemToList take a const reference to match the compiler.


BUG=
TEST=

Review URL: http://codereview.chromium.org/9423035

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@122725 0039d316-1c4b-4281-b951-d872f2087c98

gavinp/chromium,yitian134/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,gavinp/chromium,yitian134/chromium,yitian134/chromium,yitian134/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,ropik/chromium,adobe/chromium,adobe/chromium,ropik/chromium,ropik/chromium,yitian134/chromium,adobe/chromium,adobe/chromium,gavinp/chromium,yitian134/chromium,ropik/chromium,ropik/chromium,gavinp/chromium,yitian134/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,adobe/chromium,gavinp/chromium,gavinp/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,ropik/chromium