Google recently released an update for Chrome which moved the Read&Write for Google Chrome web toolbar icon from the Chrome Omnibox
If the web toolbar icon is missing, it may have been hidden.
Click on the Chrome Settings button and you’ll see any icons that have been hidden at the top of the menu list
Right click on the Read&Write for Google Chrome icon and choose Show in toolbar
That will restore the icon back to the Chrome toolbar
You can then click and drag the icon to move it anywhere in the extensions area