Add Toggle Device Mode as a chrome til

README.md

@@ -10,7 +10,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 For a steady stream of TILs from a variety of rocketeers, checkout
 [til.hashrocket.com](https://til.hashrocket.com/).
 
-_629 TILs and counting..._
+_630 TILs and counting..._
 
 ---
 
@@ -57,6 +57,7 @@ _629 TILs and counting..._
 - [Pretty Print Tabular Data](chrome/pretty-print-tabular-data.md)
 - [Reference The Selected Node](chrome/reference-the-selected-node.md)
 - [Simulating Various Connection Speeds](chrome/simulating-various-connection-speeds.md)
+- [Toggle Device Mode](chrome/toggle-device-mode.md)
 - [Toggle Open The Console Drawer](chrome/toggle-open-the-console-drawer.md)
 
 ### Clojure

chrome/toggle-device-mode.md

@@ -0,0 +1,10 @@
+# Toggle Device Mode
+
+Working on some styles? Want to make sure those minor tweaks look good on
+both desktop and mobile? Your probably moving back and forth between the
+desktop mode and one of the smaller device modes.
+
+There is a keybinding for this -- `Cmd-Shift-M`
+
+The chrome devtools panel will need to be open and in focus for this to
+work.