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.
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
