Thanks for submitting code to Blockly!  Please fill out the following as part of your pull request so we can review your code more easily.

## The basics

- [ ] I branched from develop
- [ ] My pull request is against develop
- [ ] My code follows the [style guide](https://developers.google.com/blockly/guides/modify/web/style-guide)

## The details
### Resolves

_What Github issue does this resolve (please include link)?_

### Proposed Changes

_Describe what this Pull Request does.  Include screenshots if applicable._

### Reason for Changes

_Explain why these changes should be made.  Include screenshots if applicable._

### Test Coverage

_Please show how you have added tests to cover your changes, or tell us how you tested it and on which platforms._

Tested on:
_Remove this hint: these checkboxes can be checked like this: [x]_
- [ ] Desktop:
  - [ ] Chrome
  - [ ] Firefox
  - [ ] Safari
  - [ ] Opera
  - [ ] IE 10+
  - [ ] IE 11
  - [ ] EDGE

- [ ] Smartphone/Tablet/Chromebook (please complete the following information):
  - Device: [e.g. iPhone6]
  - OS: [e.g. iOS8.1]
  - Browser [e.g. stock browser, safari]
  - Version [e.g. 22]
  
### Additional Information

_Anything else we should know?_