Pair device dialog (#1217)

* WebUSB E2E experience

* Design feedback

* adding docs

* remove i got it

* bring back download again

* updated pair dialog wording

* tweak style

* make drive name strong

* fix isAvailable -> isEnabled

* upgrading pxt reference

* fixed typo

* bump pxt

docs/SUMMARY.md

@@ -352,6 +352,7 @@
     * [Serial](/device/serial)
     * [Servo](/device/servo)
     * [Simulator](/device/simulator)
-    * [Usb](/device/usb)
+    * [USB](/device/usb)
+    * [WebUSB](/device/usb/webusb)
     * [Flashing via HID (CMSIS-DAP)](/hidflash)
 

docs/device/usb/webusb.md

@@ -0,0 +1,31 @@
+# WebUSB
+
+WebUSB is an emerging web standard that allows to access USB devices from web pages.
+It allows for a **one-click download** without installing any additional app or software! It also allows to receive data from the @boardname@.
+
+## Support
+
+* Chrome 65+ for Android, Chrome OS, Linux, macOS and Windows 10.
+
+## Upgrade your Firmware
+
+Make sure that your @boardname@ is running version **0248** or above of the firmware. Upgrading is as easy as dragging a file and it takes a few seconds to get it done.
+
+[Check out the instructions to check and upgrade your @boardname@.](https://support.microbit.org/support/solutions/articles/19000084059-beta-testing-web-usb)
+
+## Pair your device
+
+To get started with WebUSB,
+
+* connect your @boardname@ to your computer with the microUSB cable
+* open a script
+* open the gearwheel menu and select **Pair device**
+* click on the **Pair device** button and select your @boardname@ in the list
+
+## One-click Download
+
+Once your @boardname@ is paired, MakeCode will use WebUSB to transfer the code without having to drag and drop. Happy coding!
+
+## Console output
+
+MakeCode will be able to "listen" to your @boardname@ and display the console output, generated by ``console.log`` for example.

docs/device/usb/windows-chrome.md

@@ -1,5 +1,13 @@
 # Uploading from Chrome for Windows
 
+## ~ hint
+
+Starting with Chrome 65 on Windows 10, 
+you can use **WebUSB** to download with one-click.
+[Learn more about WebUSB...](/device/usb/webusb).
+
+## ~
+
 While you're writing and testing your programs, you'll mostly be [running them
 in the simulator](/device/simulator), but once you've finished your program you
 can **compile** it and run it on your micro:bit.