Enable the packed_resources target on Windows.

build/gyp_chromium

Index: build/gyp_chromium
diff --git a/build/gyp_chromium b/build/gyp_chromium
index 4b30f76669c0875d6ee233b5fd33efd738675f2c..226ba1a0f40479a499342fe31f9496803b48bfff 100755
--- a/build/gyp_chromium
+++ b/build/gyp_chromium
@@ -19,8 +19,9 @@ chrome_src = os.path.abspath(os.path.join(script_dir, os.pardir))
 sys.path.insert(0, os.path.join(chrome_src, 'tools', 'gyp', 'pylib'))
 import gyp
 
-# Add tools/grit so that pymod_do_main(grit_info ...) can find grit_info.py.
+# Add paths so that pymod_do_main(...) can import files.
 sys.path.insert(1, os.path.join(chrome_src, 'tools', 'grit'))
+sys.path.insert(1, os.path.join(chrome_src, 'chrome', 'tools', 'build'))
 
 
 # On Windows, Psyco shortens warm runs of build/gyp_chromium by about