background.html

<script>
var omnibox = chrome.omnibox;
var topMatch;
var mruTabIds = new Array();

function escape(text) {
  return text.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
}

function escapeRegexp(text) {
  var specialChars = [
    '\\',
    '[',
    ']',
    '(',
    ')',
    '|',
    '.',
    '+',
    '?',
    '{',
    '}',
    '-'
  ];

  return text.split('').map(function(char) {
    if (specialChars.indexOf(char) > -1)
      return '\\' + char;
    else
      return char;
  }).join('');
}

function parseMatches(text, search) {
  if (search == '') {
    return [
      {
        match: false,
        text: escape(text)
      }
    ];
  }
  var terms = escapeRegexp(search).split(/\s+/g);
  var termMatchCounts = [];
  terms.forEach(function() { termMatchCounts.push(0); });
  var re = new RegExp("(" + terms.join(")|(") + ")", "ig");
  var result = [];
  var lastIndex = 0;
  var match;
  while (match = re.exec(text)) {
    result.push({
      match: false,
      text: escape(text.substring(lastIndex, match.index))
    });

    lastIndex = match.index + match[0].length;
    result.push({
      match: true,
      text: escape(text.substring(match.index, lastIndex))
    });

    for (var i = 1; i < match.length; i++) {
      if (match[i])
        termMatchCounts[i - 1]++;
    }
  }

  // If any term found no matches, then we don't have a match.
  if (termMatchCounts.indexOf(0) > -1) {
    return [
      {
        match: false,
        text: escape(text)
      }
    ];
  }

  result.push({
    match: false,
    text: escape(text.substring(lastIndex))
  });

  return result;
}

function formatMatches(parsed) {
  return parsed.reduce(function(s, piece) {
    if (piece.match)
      return s + "<match>" + piece.text + "</match>";
    else
      return s + piece.text;
  }, "");
}

function formatDescription(matchItem) {
  return formatMatches(matchItem.title) + ' - ' + '<url>'
    + formatMatches(matchItem.url)+'</url>';
}

// initialize the mru tab ids to contain all of the tabs
chrome.windows.getAll({populate: true}, function(windows) {
  var tabs = windows.reduce(function(arr, win) {
    return arr.concat(win.tabs);
  }, []);
  mruTabIds = tabs.reduce(function(ids, tab) {
      return ids.concat(tab.id);
  }, []);
});

chrome.tabs.onCreated.addListener(function(tab) {
  mruTabIds.push(tab.id);
});

chrome.tabs.onSelectionChanged.addListener(function(tabId, selectInfo) {
  if (mruTabIds.indexOf(tabId) != -1) {
    mruTabIds.splice(mruTabIds.indexOf(tabId), 1);
    mruTabIds.splice(0,0,tabId);
  }
});

chrome.tabs.onRemoved.addListener(function(tabId) {
  if(mruTabIds.indexOf(tabId) != -1)
    mruTabIds.splice(mruTabIds.indexOf(tabId), 1);
});

omnibox.onInputChanged.addListener(function(text, suggest) {
  text = text.toLowerCase().replace(/\W+/g, ' ').trim();

  chrome.windows.getAll({populate: true}, function(windows) {
    topMatch = -1;
    var tabs = windows.reduce(function(arr, win) {
      return arr.concat(win.tabs);
    }, []);

    var tabIds = tabs.reduce(function(ids, tab) {
        return ids.concat(tab.id);
    }, []);

    var suggestions = mruTabIds.map(function(id) {
      if (mruTabIds.indexOf(id) == 0) return null; // index 0 is the current tab, no need to handle it
      var idx = tabIds.indexOf(id);
      if (idx != -1 && tabs[idx]) {
        return {
          tab: tabs[idx],
          title: parseMatches(tabs[idx].title, text),
          url: parseMatches(tabs[idx].url, text)
        };
      }
      return null;
    }).filter(function(item) {
      if (item && (text == '' || item.title.length > 1 || item.url.length > 1)) {
        if (topMatch == -1)
          topMatch = item;
        return true;
      } else {
        return false;
      }
    }).map(function(item) {
      return {
        content: item.tab.url + ' #' + item.tab.id,
        description: formatDescription(item)
      };
    });
    updateDefaultSuggestion();
    suggest(suggestions);
  });
});

omnibox.onInputEntered.addListener(function(url) {
  var tabId = url.match(/#(\d+)$/);
  if (tabId)
    tabId = parseInt(tabId[1]);
  else if (topMatch != -1)
    tabId = topMatch.tab.id;
  else
    return;

  chrome.tabs.get(tabId, function(tab) {
    if (tab && !tab.selected) {
      chrome.tabs.update(tabId, {
        selected: true
      });
    }

    chrome.windows.get(tab.windowId, function(win) {
      if (!window.focused) {
        chrome.windows.update(tab.windowId, {
          focused: true
        });
      }
    });
  });
});

//omnibox.onInputCancelled.addListener(function() {
//  topMatch = -1;
//});

function updateDefaultSuggestion() {
  var description = "No default tab to switch";
  if (topMatch != -1) {
    description='Switch to: ' + formatDescription(topMatch);
  }
  omnibox.setDefaultSuggestion({
    description: description
  });
}

</script>