How do you expand all elements in the WebKit Inspector elements view?
Solution 1:
If you hold ctrl + alt for windows (just opt on a mac) while clicking on the arrow of the element you want to expand, it will expand and all of its children will expand. So, if you ctrl + alt click on the <html> tag, that should expand the entire page.
This Link lists the keyboard shortcuts for chrome dev tools, including that one.
Solution 2:
CTRL + SHIFT + ALT + LEFTCLICK