update_payload: deprecate unused flags from paycheck.py

Some temporary workaround are placed to hack the parameters to some
default value that the rest of the code is happy with. This CL removes
them.

part_sizes should be default None (it was default [None, None]).
when part_sizes is None, part sizes are not checked (same behavior as
[None, None]).
src_part_paths should be default None (it was default [None, None]).
when src_part_paths is None, we set args.assert_type=_TYPE_FULL (same
behavior as [None, None]).
dst_part_paths (out_dst_part_paths) should be default None (it was
default [None, None]).
when dst_part_paths (and out_dst_part_paths) is None, dargs is not set
(same behavior as [None, None]).
out_dst_part_paths is rarely used and we often chose to use
dst_part_path.

Old flags (deprecated) are removed as well.

BUG=chromium:926045
TEST=test_paycheck.sh chromeos_11844.0.0_kevin-arcnext_canary-channel_full_kevin-mp.bin-6f7f58b3c9a1a84ea15ab67f84cd5387.signed chromeos_11844.0.0-11869.0.0_kevin-arcnext_canary-channel_delta_kevin-mp.bin-fc6014025415e0b5e780c0739a3b0461.signed chromeos_11869.0.0_kevin-arcnext_canary-channel_full_kevin-mp.bin-1be744e0723534e02084c762dea316c0.signed

Change-Id: Ifdf872ddfa03d5759a8ee4021e296e4dc4571d9c
Reviewed-on: https://chromium-review.googlesource.com/1525289
Commit-Ready: Xiaochu Liu <xiaochu@chromium.org>
Tested-by: Xiaochu Liu <xiaochu@chromium.org>
Reviewed-by: Nicolas Norvez <norvez@chromium.org>
diff --git a/scripts/update_payload/checker.py b/scripts/update_payload/checker.py
index 6d17fbe..e4fec2d 100644
--- a/scripts/update_payload/checker.py
+++ b/scripts/update_payload/checker.py
@@ -609,7 +609,7 @@
     """
     self.major_version = self.payload.header.version
 
-    part_sizes = collections.defaultdict(int, part_sizes)
+    part_sizes = part_sizes or collections.defaultdict(int)
     manifest = self.payload.manifest
     report.AddSection('manifest')
 
@@ -1372,7 +1372,7 @@
         new_fs_usable_size = self.new_fs_sizes[part]
         old_fs_usable_size = self.old_fs_sizes[part]
 
-        if part_sizes.get(part, None):
+        if part_sizes is not None and part_sizes.get(part, None):
           new_fs_usable_size = old_fs_usable_size = part_sizes[part]
         # Infer the usable partition size when validating rootfs operations:
         # - If rootfs partition size was provided, use that.