Teach sort-headers.py about windows.h.

See http://groups.google.com/a/chromium.org/group/chromium-dev/browse_thread/thread/a3480ba1e7b8b9c0#

BUG=none
TEST=Run sort-headers.py on a file that includes <windows.h>, e.g. base/file_util_unittest.cc. That line should stay at the top of its block.

Review URL: http://codereview.chromium.org/7050020

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@85957 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/tools/sort-headers.py b/tools/sort-headers.py
index b18ac6c..d7633e8 100755
--- a/tools/sort-headers.py
+++ b/tools/sort-headers.py
@@ -34,7 +34,12 @@
   """
   for prefix in ('#include ', '#import '):
     if line.startswith(prefix):
-      return line[len(prefix):]
+      line = line[len(prefix):]
+      break
+  # <windows.h> needs to be before other includes, so return a key
+  # that's less than all other keys.
+  if line.lstrip().startswith('<windows.h>'):
+    return ''
   return line