A few years ago I wrote about ExtJS4 Dev Tools of a Pro, where I mentioned a FireFox plugin called Illuminations. Since then I've switched to Chrome as my dev platform where I missed my cherished Illuminations plugin.
I believe only last week the creators of FF's plugin have released a version for Chrome: https://chrome.google.com/webstore/detail/illuminations/hbhnkfhblakpfhcpepeoogmakimflibk
It doesn't feel like a full port, but it does have the one feature I care most about: similar to how you can right-click on a page and "Inspect Element" to bring up dev tools and pinpoint the target in the DOM tree, you can now right-click and "Illuminate:"
At which point you will pinpoint the target in the Ext component tree:
Combined with Sencha Inspector for Chrome, the Chrome browser is now a powerhouse for ExtJS/Sencha Touch development!