Refactor building unit_tests with SCons for the new structure:
* Rename SConscript.unit_tests to test/unit/unit_tests.scons.
* Add a new chrome/chrome.scons "master" for building everything
  chrome.  Have it just load the existing SConscript file, and
  the new test/unit/unit_tests.scons file.  We'll move things from
  SConscript (or elsewhere) into chrome.scons as they get convertd.
* Change build/SConscript.main to load chrome/chrome.scons.
* Add new using_libjpeg.scons, using_libxml.scons, and using_libxslt.scons
  "properties" files.
* Convert test/unit/unit_tests.scons to use the available using_*.scons files.
* Combine settings that were scattered throught test/unit/unit_tests.scons
  to make it a little more readable.
* Add $CHROME_DIR/ to the beginning of the file listed in
  test/unit/unit_tests.scons, since they're now being interpreted
  from a SConscript file down two directory levels.
Review URL: http://codereview.chromium.org/9005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@4448 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/chrome.scons b/chrome/chrome.scons
new file mode 100644
index 0000000..4e4cfad
--- /dev/null
+++ b/chrome/chrome.scons
@@ -0,0 +1,17 @@
+# Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+__doc__ = """
+Master configuration for building chrome components.
+"""
+
+Import('env')
+
+sconscript_files = [
+    'SConscript',
+
+    'test/unit/unit_tests.scons',
+]
+
+SConscript(sconscript_files, exports=['env'])