releasetools: Allow verifying chained vbmeta partitions.

Chained vbmeta partitions (vbmeta_system, vbmeta_vendor) were added to
support dynamic partitions. validate_target_files.py misses the logic in
handling such partitions.

Bug: 132882632
Test: Run validate_target_files.py on a target_files.zip that uses
      chained vbmeta_system partition.
Change-Id: Id06c575d13d5e9cc1b621f485ceb75d3e354c39f
Merged-In: Id06c575d13d5e9cc1b621f485ceb75d3e354c39f
(cherry picked from commit 814b14b3f79da4062335413b79284864b185a4b9)
diff --git a/tools/releasetools/validate_target_files.py b/tools/releasetools/validate_target_files.py
index 1c856a8..37d5d27 100755
--- a/tools/releasetools/validate_target_files.py
+++ b/tools/releasetools/validate_target_files.py
@@ -327,11 +327,14 @@
     cmd = ['avbtool', 'verify_image', '--image', image, '--key', key]
 
     # Append the args for chained partitions if any.
-    for partition in common.AVB_PARTITIONS:
+    for partition in common.AVB_PARTITIONS + common.AVB_VBMETA_PARTITIONS:
       key_name = 'avb_' + partition + '_key_path'
       if info_dict.get(key_name) is not None:
+        # Use the key file from command line if specified; otherwise fall back
+        # to the one in info dict.
+        key_file = options.get(key_name, info_dict[key_name])
         chained_partition_arg = common.GetAvbChainedPartitionArg(
-            partition, info_dict, options[key_name])
+            partition, info_dict, key_file)
         cmd.extend(["--expected_chain_partition", chained_partition_arg])
 
     proc = common.Run(cmd)
@@ -357,7 +360,7 @@
       help='the verity public key to verify the bootable images (Verified '
            'Boot 1.0), or the vbmeta image (Verified Boot 2.0, aka AVB), where '
            'applicable')
-  for partition in common.AVB_PARTITIONS:
+  for partition in common.AVB_PARTITIONS + common.AVB_VBMETA_PARTITIONS:
     parser.add_argument(
         '--avb_' + partition + '_key_path',
         help='the public or private key in PEM format to verify AVB chained '