DevTools: do not show Replace checkbox while searching read-only views

SearchableView._updateReplaceVisibility() bails out if (!searchVisble),
so make sure to update searchVisible before calling updateReplaceVisibility,
othwerwise first invocation of search on Timeline offers "Replace" checkbox.

R=vsevik

Review URL: https://codereview.chromium.org/114133002

git-svn-id: svn://svn.chromium.org/blink/trunk@163958 bbb929c8-8fbe-4397-9dbb-9b2b20218538