hide subtitle download button for files not saved

we are hiding the download button for subtitles that haven't
been saved yet. When we add an edit mode, the download button
can be shown there.

Test Plan:
- in A2 as a student start a media submission
- add a subtitle file with language selection to your media
- see that the download button does not show

closes COMMS-2410
flag=assignments_2

Change-Id: I6b489a6296bf7472e62e2699aff647bf95b8ea3e
Reviewed-on: https://gerrit.instructure.com/208825
Reviewed-by: Steven Burnett <sburnett@instructure.com>
QA-Review: Steven Burnett <sburnett@instructure.com>
Tested-by: Jenkins
Product-Review: Ben Nelson <bnelson@instructure.com>

packages/canvas-media/src/ClosedCaptionCreator/ClosedCaptionRow.js

@@ -36,9 +36,11 @@ export default function ClosedCaptionRow({closedCaption, trashButtonOnClick}) {
         <Text>{closedCaption.file.name}</Text>
       </Flex.Item>
       <Flex.Item textAlign="end" shrink grow>
-        <Button variant="icon" icon={IconDownloadLine}>
-          <ScreenReaderContent>Download {closedCaption.file.name}</ScreenReaderContent>
-        </Button>
+        {!closedCaption.isNew && (
+          <Button variant="icon" icon={IconDownloadLine}>
+            <ScreenReaderContent>Download {closedCaption.file.name}</ScreenReaderContent>
+          </Button>
+        )}
         <Button variant="icon" icon={IconTrashLine} onClick={onRowDelete}>
           <ScreenReaderContent>Delete {closedCaption.file.name}</ScreenReaderContent>
         </Button>

packages/canvas-media/src/ClosedCaptionCreator/__tests__/ClosedCaptionRow.test.js

@@ -29,7 +29,8 @@ function makeProps() {
       },
       file: {
         name: 'bestfileever.webvtt'
-      }
+      },
+      isNew: true
     },
     trashButtonOnClick: () => {}
   }
@@ -40,7 +41,6 @@ describe('ClosedCaptionRow', () => {
     const {getByText} = render(<ClosedCaptionRow {...makeProps()} />)
     expect(getByText('english')).toBeInTheDocument()
     expect(getByText('bestfileever.webvtt')).toBeInTheDocument()
-    expect(getByText('Download bestfileever.webvtt')).toBeInTheDocument()
     expect(getByText('Delete bestfileever.webvtt')).toBeInTheDocument()
   })
 

packages/canvas-media/src/ClosedCaptionCreator/index.js

@@ -55,7 +55,12 @@ export default class ClosedCaptionPanel extends Component {
       e.persist()
       this.setState(prevState => {
         const subtitles = prevState.subtitles.concat([
-          {id: shortId(), language: prevState.newSelectedLanguage, file: e.target.files[0]}
+          {
+            id: shortId(),
+            language: prevState.newSelectedLanguage,
+            file: e.target.files[0],
+            isNew: true
+          }
         ])
         this.props.updateSubtitles(subtitles)
         return {
@@ -74,7 +79,7 @@ export default class ClosedCaptionPanel extends Component {
     if (this.state.newSelectedFile) {
       this.setState(prevState => {
         const subtitles = prevState.subtitles.concat([
-          {id: shortId(), language: option, file: prevState.newSelectedFile}
+          {id: shortId(), language: option, file: prevState.newSelectedFile, isNew: true}
         ])
         this.props.updateSubtitles(subtitles)
         return {