when suggestions show, pinned bookmark bar and infobars would hide, causing contents to shift up. if ESC is hit to cancel the query, the bars would then appear, causing contents to shift down. all these cause jankiness. this cl is the first in the line to fix such jankiness: - tackle website pages where suggestions appear in a preview overlay - modify infobar container to delay hiding its bars until instant preview is ready, instead of when user starts typing - during layout, if preview is taller than all hidden bars, preserve the position that contents previously had with the visible bars by setting a top margin in contents container later cls will tackle ntp and serp pages where suggestions appear in the contents, so showing and hiding of bars require synchronization with renderer's searchbox api. BUG=171075 TEST=verify per bug rpt Review URL: https://chromiumcodereview.appspot.com/12036075 git-svn-id: svn://svn.chromium.org/chrome/trunk/src@180439 0039d316-1c4b-4281-b951-d872f2087c98