This is the very first step towards a clearer way to organize and
state dependencies between targets: for now we just remove this
target and fold everything into //chrome/browser via a massive
dump into browser/sources.gni with no further changes, plus the
necessary adaptations wherever the old target was referenced.
Once this is in place, next steps will extract different subsets
of the sources dumped in there into separate .gni files, so that
it can be more clearly stated which dependencies are actually
related to which subset of source files, instead of having the
giant merge of dependencies we had until now in a single target.
Once those separate .gni files are in place, and each of them
with their own clear set of dependencies, we should be in a much
better position to reorganize things and see what can be moved
around into independent GN targets instead of being part of the
//chrome/browser main target.
Finally, this change also makes the //brave/browser target a group
instead of a source_set and adjust visibility rules in a more
precise way, so that we can still reference //brave/browser from
different places in Brave (vs having to reference //chrome/browser).
Mario Sanchez Prada
577eba4cdc