Add reporting of the uncompressed size in the chunk timings

[pmeenan]

This adds a "filtered" size entry to the chunk timings that carries the decompressed size of resources that are content-encoded (gzip, brotli).

    "chunks": [
        {
            "ts": 444,
            "bytes": 1387,
            "filtered": 2985
        },
        {
            "ts": 446,
            "bytes": 1396,
            "filtered": 3677
        },
        {
            "ts": 466,
            "bytes": 1396,
            "filtered": 3888
        },

This will make it possible to map individual chunks of HTML back to when they were flushed.

Some possible uses come to mind:

• Highlight the time in the waterfall when the LCP image element was delivered on the wire.
• Provide a UI that shows the raw HTML response body and match selection or cursor position to where in the waterfall entry that chunk of HTML was delivered.