Fix various stray bugs in the GN auto-roller, and repair the DEPS file.

DEPS

Index: DEPS
diff --git a/DEPS b/DEPS
index c2dd796f42562a92b02e66461cf0042f7460ab4f..287eb9cf1bf660f2d19d5f1612185543645eb194 100644
--- a/DEPS
+++ b/DEPS
@@ -51,7 +51,9 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling build tools
   # and whatever else without interference from each other.
-  'buildtools_revision': '565d04e8741429fb1b4f26d102f2c6c3b849edeb',  # the commit queue can handle CLs rolling PDFium
+  'buildtools_revision': '565d04e8741429fb1b4f26d102f2c6c3b849edeb',
+  # Three lines of non-changing comments so that
+  # the commit queue can handle CLs rolling PDFium
   # and whatever else without interference from each other.
   'pdfium_revision': 'fdc8f439e854a2636e7d22d7104bf08cf5620b0b',
   # Three lines of non-changing comments so that