iOS Google Takeout file Download Fixes #77

[popofibo]

Fixes #77

This existing react-native-webview bug will be auto-fixed in their next release with this PR. This fix will be a workaround to handle file downloads for iOS by:

• Intercepting WebView call to check for iOS and if url equates to takeout download url (onShouldStartLoadWithRequest)
• Creates a directory within AppData documents
• Saves the takeout file and unzips as normal

Tested on iOS and Android

[kenpugsley]

We need to review this to determine if it's required for the v1.0 release. @popofibo - do you know if iOS export is fundamentally broken without this change?

[popofibo]

We need to review this to determine if it's required for the v1.0 release. @popofibo - do you know if iOS export is fundamentally broken without this change?

iOS import with react native webview is definitely broken w/o this change; I referenced to the link in my comment above of the PR to core react native webview package that fixes it more gracefully. The core webview change essentially adds an optional callback onFileDownload, my code above takes a similar approach but uses available onShouldStartLoadWithRequest to intercept and create a downloads folder within the application, and saves the file to be utilized.

[popofibo]

cc: @kenpugsley @tremblerz if this is to be merged before it starts to conflict

[kenpugsley]

Leaving this PR, but moving to "next next" the version right after v1.0. Since final translations are already underway, I think the best plan is to merge this in to develop right after the rc-1.0 branch is created. That will put this functionality into the first update after v1.0.

[tstirrat]

This will be superseded by #410 as we will remove the webview.

[sergesemashko]

I think this PR can be closed in favor of #410 as it also takes care of issue #77.