Merge 158559 - Fix toolbar keyboard accessibility if bookmarks bar is shown.

Merge 158559 - Fix toolbar keyboard accessibility if bookmarks bar is shown.

If the bookmarks bar was shown on startup, toolbar focus searching
was broken because the code that tried to override the focus search
order of the location bar container got undone when the bookmarks
bar became a sibling of the location bar container. To fix this,
overriding the focus search order is now done dynamically when the
toolbar gets focus.

Adds a new test for this case.

BUG=151747
Review URL: https://chromiumcodereview.appspot.com/10962048

TBR=dmazzoni@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=158891