Reland "[DevTools] Add a flag --enable-devtools-binary-protocol for DevToolsSession."

This is a reland of 6ab258258c8ba0c7ebda22756062abc720859b6a

Original change's description:
> [DevTools] Add a flag --enable-devtools-binary-protocol for DevToolsSession.
> 
> When the flag is enabled, we send messages to agents / handlers as CBOR,
> even if the cient sends us JSON. We convert responses back to JSON if
> needed.
> 
> Change-Id: I6123e38262d6eeb82206d28a936a32f7db8235b8
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1507232
> Commit-Queue: Johannes Henkel <[email protected]>
> Reviewed-by: Pavel Feldman <[email protected]>
> Reviewed-by: Andrey Kosyakov <[email protected]>
> Cr-Commit-Position: refs/heads/master@{#638897}

Change-Id: I20975e3119d3ac65a3e4294ea7cf0bf2d9516389
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1512336
Reviewed-by: Johannes Henkel <[email protected]>
Reviewed-by: Pavel Feldman <[email protected]>
Commit-Queue: Pavel Feldman <[email protected]>
Cr-Commit-Position: refs/heads/master@{#639164}
11 files changed