chrome.gyp fixes to preserve various build behaviors...

chrome.gyp fixes to preserve various build behaviors
and clean up some things:
* Make <(grit_out_dir) a top-level variable, used by multiple targets.
* Add precompiled.{cc,h} to various targets:  common and plugin.
* Add precompiled_wtl.{cc,h} to various targets:  renderer, unit_tests,
  and url_fetch_test.
* Add browser/net/test_url_fetcher_factory.cc to unit_tests.
* Add dependencies on net_resources and webkit_resources to unit_tests
  and interactive_ui_tests.
* Add a dependency on test_support_common to page_cycler_tests.
* Add a dependency on net to url_fetch_test.
* Pull in all of the installer/installer.gyp targets.
BUG=none
TEST=none

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=17174

[bradn, 2009-05-28 23:43:58]

LGTM