Javadoc incremental search for packages and classes.
When viewing Javadocs, this extension replaces the package and class frames with a single search frame that allows searching incrementally through all packages and classes at once.
Feature summary: https://github.com/StevenGBrown/javadoc-search-frame/wiki/Features
To have this extension apply to file:// URLs, configure it from the chrome://extensions/ page.
Also available for Mozilla Firefox: