Fix: Ensure the scrollbars are always restored

[0nko]

Task/Issue URL: https://app.asana.com/1/137249556945/project/1207418217763355/task/1210108991225075?focus=true

Description

This fixes a bug when the WebView scrollbars would stay hidden if the preview generation threw an exception. This may happen fairly often with tab swiping when you swipe between tabs fast so that the webview doesn't get a chance to get laid out.

Steps to test this PR

• Swipe tabs until you notice Failed to generate WebView preview in the logcat
• Swipe back to the last tab
• Notice the WebView has scrollbars when you scroll it

[CDRussell]

nit: don't think you need to have val scaledBitmap: Bitmap and return scaledBitmap separately; could just make it part of the return statement at the end of the try block. marginally easier to read IMO.

try {
    disableScrollbars(webView)
    val fullSizeBitmap = createBitmap(webView)

    val scaledHeight = webView.context.resources.getDimension(R.dimen.gridItemPreviewHeight).toPx()
    val scaledWidth = scaledHeight / fullSizeBitmap.height * fullSizeBitmap.width
    return scaleBitmap(fullSizeBitmap, scaledHeight.roundToInt(), scaledWidth.roundToInt())
} finally {
    enableScrollbars(webView)
}

[0nko]

Good call, thanks!