Some times I inadvertently clear history in the search box and there is no way to recover the history. I lose months worth of search terms that I use to navigate among websites rather than using bookmarks.
Normally I type two or three letters into the search box and then click on the stored search term.
One inadvertent keystroke or mouse click and it's gone. How about making it a two-step process with a dialog box that asks, "Are you sure you want to clear history?" and offer a chance to click a yes or no button to confirm or refuse the action
Or maybe offer an undo function for clear history.