The idea originally was that the WebContentConsoleClient would perform
some amount of console handling that both InspectorConsoleClient and
DevToolsConsoleClient needed. But in implementing the DevTools console,
it's become clear that these implementations will not overlap at all. So
this patch moves the existing Inspector functionality away from
WebContentConsoleClient.
Our existing WebContentConsoleClient is very specific to our home-grown
Inspector. It renders console output to an HTML string. For DevTools, we
will not want this behavior; we will want to send representations of raw
JS values.
This patch makes WebContentConsoleClient a base class to handle console
input from the user, either from the Inspector or from DevTools. It then
moves the HTML rendering needed for the Inspector to a new class,
InspectorConsoleClient. And we add a DevToolsConsoleClient (currently
just stubbed) to handle needs specific to DevTools.
We choose at runtime which console client to install, based on the
--devtools command line flag.
