Fix for gyp release build.
Fix for gyp release build.

Apparently the compiler optimized unique_ in
InterfaceTraits to all point to the same thing
since it was marked as const.  Making it non-const
seems to fix it.

Review URL: http://codereview.chromium.org/165419

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@23369 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser