trunk-tracking: port tests for r3935 which changes image lazyloading
trunk-tracking: port tests for r3935 which changes image lazyloading

digideskio/ngx_pagespeed,digideskio/ngx_pagespeed,0x0mar/ngx_pagespeed,pagespeed/ngx_pagespeed,wanrui/ngx_pagespeed,pagespeed/ngx_pagespeed,0x0mar/ngx_pagespeed,wanrui/ngx_pagespeed