diff --git a/payload_generator/delta_diff_generator.cc b/payload_generator/delta_diff_generator.cc
index 74d43fd..f008d40 100644
--- a/payload_generator/delta_diff_generator.cc
+++ b/payload_generator/delta_diff_generator.cc
@@ -127,6 +127,7 @@
     for (const AnnotatedOperation& aop : *aops_) {
       *operations.Add() = aop.op;
     }
+    // TODO(177936022) Skip cow size estimation if VABC isn't enabled
     *cow_size_ = EstimateCowSize(
         source_fd,
         std::move(target_fd),
diff --git a/payload_generator/payload_generation_config.cc b/payload_generator/payload_generation_config.cc
index ef2f240..f5a7062 100644
--- a/payload_generator/payload_generation_config.cc
+++ b/payload_generator/payload_generation_config.cc
@@ -176,6 +176,10 @@
   bool snapshot_enabled = false;
   store.GetBoolean("virtual_ab", &snapshot_enabled);
   metadata->set_snapshot_enabled(snapshot_enabled);
+  bool vabc_enabled = false;
+  if (store.GetBoolean("virtual_ab_compression", &vabc_enabled)) {
+    metadata->set_vabc_enabled(vabc_enabled);
+  }
 
   dynamic_partition_metadata = std::move(metadata);
   return true;
diff --git a/scripts/update_payload/update_metadata_pb2.py b/scripts/update_payload/update_metadata_pb2.py
index ea4bc59..9fcd3b9 100644
--- a/scripts/update_payload/update_metadata_pb2.py
+++ b/scripts/update_payload/update_metadata_pb2.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: update_metadata.proto
-
+"""Generated protocol buffer code."""
 from google.protobuf import descriptor as _descriptor
 from google.protobuf import message as _message
 from google.protobuf import reflection as _reflection
@@ -18,7 +18,8 @@
   package='chromeos_update_engine',
   syntax='proto2',
   serialized_options=b'H\003',
-  serialized_pb=b'\n\x15update_metadata.proto\x12\x16\x63hromeos_update_engine\"1\n\x06\x45xtent\x12\x13\n\x0bstart_block\x18\x01 \x01(\x04\x12\x12\n\nnum_blocks\x18\x02 \x01(\x04\"\x9f\x01\n\nSignatures\x12@\n\nsignatures\x18\x01 \x03(\x0b\x32,.chromeos_update_engine.Signatures.Signature\x1aO\n\tSignature\x12\x13\n\x07version\x18\x01 \x01(\rB\x02\x18\x01\x12\x0c\n\x04\x64\x61ta\x18\x02 \x01(\x0c\x12\x1f\n\x17unpadded_signature_size\x18\x03 \x01(\x07\"+\n\rPartitionInfo\x12\x0c\n\x04size\x18\x01 \x01(\x04\x12\x0c\n\x04hash\x18\x02 \x01(\x0c\"w\n\tImageInfo\x12\r\n\x05\x62oard\x18\x01 \x01(\t\x12\x0b\n\x03key\x18\x02 \x01(\t\x12\x0f\n\x07\x63hannel\x18\x03 \x01(\t\x12\x0f\n\x07version\x18\x04 \x01(\t\x12\x15\n\rbuild_channel\x18\x05 \x01(\t\x12\x15\n\rbuild_version\x18\x06 \x01(\t\"\xee\x03\n\x10InstallOperation\x12;\n\x04type\x18\x01 \x02(\x0e\x32-.chromeos_update_engine.InstallOperation.Type\x12\x13\n\x0b\x64\x61ta_offset\x18\x02 \x01(\x04\x12\x13\n\x0b\x64\x61ta_length\x18\x03 \x01(\x04\x12\x33\n\x0bsrc_extents\x18\x04 \x03(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x12\n\nsrc_length\x18\x05 \x01(\x04\x12\x33\n\x0b\x64st_extents\x18\x06 \x03(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x12\n\ndst_length\x18\x07 \x01(\x04\x12\x18\n\x10\x64\x61ta_sha256_hash\x18\x08 \x01(\x0c\x12\x17\n\x0fsrc_sha256_hash\x18\t \x01(\x0c\"\xad\x01\n\x04Type\x12\x0b\n\x07REPLACE\x10\x00\x12\x0e\n\nREPLACE_BZ\x10\x01\x12\x0c\n\x04MOVE\x10\x02\x1a\x02\x08\x01\x12\x0e\n\x06\x42SDIFF\x10\x03\x1a\x02\x08\x01\x12\x0f\n\x0bSOURCE_COPY\x10\x04\x12\x11\n\rSOURCE_BSDIFF\x10\x05\x12\x0e\n\nREPLACE_XZ\x10\x08\x12\x08\n\x04ZERO\x10\x06\x12\x0b\n\x07\x44ISCARD\x10\x07\x12\x11\n\rBROTLI_BSDIFF\x10\n\x12\x0c\n\x08PUFFDIFF\x10\t\"\xcf\x01\n\x11\x43owMergeOperation\x12<\n\x04type\x18\x01 \x01(\x0e\x32..chromeos_update_engine.CowMergeOperation.Type\x12\x32\n\nsrc_extent\x18\x02 \x01(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x32\n\ndst_extent\x18\x03 \x01(\x0b\x32\x1e.chromeos_update_engine.Extent\"\x14\n\x04Type\x12\x0c\n\x08\x43OW_COPY\x10\x00\"\xc8\x06\n\x0fPartitionUpdate\x12\x16\n\x0epartition_name\x18\x01 \x02(\t\x12\x17\n\x0frun_postinstall\x18\x02 \x01(\x08\x12\x18\n\x10postinstall_path\x18\x03 \x01(\t\x12\x17\n\x0f\x66ilesystem_type\x18\x04 \x01(\t\x12M\n\x17new_partition_signature\x18\x05 \x03(\x0b\x32,.chromeos_update_engine.Signatures.Signature\x12\x41\n\x12old_partition_info\x18\x06 \x01(\x0b\x32%.chromeos_update_engine.PartitionInfo\x12\x41\n\x12new_partition_info\x18\x07 \x01(\x0b\x32%.chromeos_update_engine.PartitionInfo\x12<\n\noperations\x18\x08 \x03(\x0b\x32(.chromeos_update_engine.InstallOperation\x12\x1c\n\x14postinstall_optional\x18\t \x01(\x08\x12=\n\x15hash_tree_data_extent\x18\n \x01(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x38\n\x10hash_tree_extent\x18\x0b \x01(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x1b\n\x13hash_tree_algorithm\x18\x0c \x01(\t\x12\x16\n\x0ehash_tree_salt\x18\r \x01(\x0c\x12\x37\n\x0f\x66\x65\x63_data_extent\x18\x0e \x01(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x32\n\nfec_extent\x18\x0f \x01(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x14\n\tfec_roots\x18\x10 \x01(\r:\x01\x32\x12\x0f\n\x07version\x18\x11 \x01(\t\x12\x43\n\x10merge_operations\x18\x12 \x03(\x0b\x32).chromeos_update_engine.CowMergeOperation\x12\x19\n\x11\x65stimate_cow_size\x18\x13 \x01(\x04\"L\n\x15\x44ynamicPartitionGroup\x12\x0c\n\x04name\x18\x01 \x02(\t\x12\x0c\n\x04size\x18\x02 \x01(\x04\x12\x17\n\x0fpartition_names\x18\x03 \x03(\t\"s\n\x18\x44ynamicPartitionMetadata\x12=\n\x06groups\x18\x01 \x03(\x0b\x32-.chromeos_update_engine.DynamicPartitionGroup\x12\x18\n\x10snapshot_enabled\x18\x02 \x01(\x08\"\xe1\x06\n\x14\x44\x65ltaArchiveManifest\x12H\n\x12install_operations\x18\x01 \x03(\x0b\x32(.chromeos_update_engine.InstallOperationB\x02\x18\x01\x12O\n\x19kernel_install_operations\x18\x02 \x03(\x0b\x32(.chromeos_update_engine.InstallOperationB\x02\x18\x01\x12\x18\n\nblock_size\x18\x03 \x01(\r:\x04\x34\x30\x39\x36\x12\x19\n\x11signatures_offset\x18\x04 \x01(\x04\x12\x17\n\x0fsignatures_size\x18\x05 \x01(\x04\x12\x42\n\x0fold_kernel_info\x18\x06 \x01(\x0b\x32%.chromeos_update_engine.PartitionInfoB\x02\x18\x01\x12\x42\n\x0fnew_kernel_info\x18\x07 \x01(\x0b\x32%.chromeos_update_engine.PartitionInfoB\x02\x18\x01\x12\x42\n\x0fold_rootfs_info\x18\x08 \x01(\x0b\x32%.chromeos_update_engine.PartitionInfoB\x02\x18\x01\x12\x42\n\x0fnew_rootfs_info\x18\t \x01(\x0b\x32%.chromeos_update_engine.PartitionInfoB\x02\x18\x01\x12\x39\n\x0eold_image_info\x18\n \x01(\x0b\x32!.chromeos_update_engine.ImageInfo\x12\x39\n\x0enew_image_info\x18\x0b \x01(\x0b\x32!.chromeos_update_engine.ImageInfo\x12\x18\n\rminor_version\x18\x0c \x01(\r:\x01\x30\x12;\n\npartitions\x18\r \x03(\x0b\x32\'.chromeos_update_engine.PartitionUpdate\x12\x15\n\rmax_timestamp\x18\x0e \x01(\x03\x12T\n\x1a\x64ynamic_partition_metadata\x18\x0f \x01(\x0b\x32\x30.chromeos_update_engine.DynamicPartitionMetadata\x12\x16\n\x0epartial_update\x18\x10 \x01(\x08\x42\x02H\x03'
+  create_key=_descriptor._internal_create_key,
+  serialized_pb=b'\n\x15update_metadata.proto\x12\x16\x63hromeos_update_engine\"1\n\x06\x45xtent\x12\x13\n\x0bstart_block\x18\x01 \x01(\x04\x12\x12\n\nnum_blocks\x18\x02 \x01(\x04\"\x9f\x01\n\nSignatures\x12@\n\nsignatures\x18\x01 \x03(\x0b\x32,.chromeos_update_engine.Signatures.Signature\x1aO\n\tSignature\x12\x13\n\x07version\x18\x01 \x01(\rB\x02\x18\x01\x12\x0c\n\x04\x64\x61ta\x18\x02 \x01(\x0c\x12\x1f\n\x17unpadded_signature_size\x18\x03 \x01(\x07\"+\n\rPartitionInfo\x12\x0c\n\x04size\x18\x01 \x01(\x04\x12\x0c\n\x04hash\x18\x02 \x01(\x0c\"\x8f\x01\n\tImageInfo\x12\x11\n\x05\x62oard\x18\x01 \x01(\tB\x02\x18\x01\x12\x0f\n\x03key\x18\x02 \x01(\tB\x02\x18\x01\x12\x13\n\x07\x63hannel\x18\x03 \x01(\tB\x02\x18\x01\x12\x13\n\x07version\x18\x04 \x01(\tB\x02\x18\x01\x12\x19\n\rbuild_channel\x18\x05 \x01(\tB\x02\x18\x01\x12\x19\n\rbuild_version\x18\x06 \x01(\tB\x02\x18\x01\"\xee\x03\n\x10InstallOperation\x12;\n\x04type\x18\x01 \x02(\x0e\x32-.chromeos_update_engine.InstallOperation.Type\x12\x13\n\x0b\x64\x61ta_offset\x18\x02 \x01(\x04\x12\x13\n\x0b\x64\x61ta_length\x18\x03 \x01(\x04\x12\x33\n\x0bsrc_extents\x18\x04 \x03(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x12\n\nsrc_length\x18\x05 \x01(\x04\x12\x33\n\x0b\x64st_extents\x18\x06 \x03(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x12\n\ndst_length\x18\x07 \x01(\x04\x12\x18\n\x10\x64\x61ta_sha256_hash\x18\x08 \x01(\x0c\x12\x17\n\x0fsrc_sha256_hash\x18\t \x01(\x0c\"\xad\x01\n\x04Type\x12\x0b\n\x07REPLACE\x10\x00\x12\x0e\n\nREPLACE_BZ\x10\x01\x12\x0c\n\x04MOVE\x10\x02\x1a\x02\x08\x01\x12\x0e\n\x06\x42SDIFF\x10\x03\x1a\x02\x08\x01\x12\x0f\n\x0bSOURCE_COPY\x10\x04\x12\x11\n\rSOURCE_BSDIFF\x10\x05\x12\x0e\n\nREPLACE_XZ\x10\x08\x12\x08\n\x04ZERO\x10\x06\x12\x0b\n\x07\x44ISCARD\x10\x07\x12\x11\n\rBROTLI_BSDIFF\x10\n\x12\x0c\n\x08PUFFDIFF\x10\t\"\xcf\x01\n\x11\x43owMergeOperation\x12<\n\x04type\x18\x01 \x01(\x0e\x32..chromeos_update_engine.CowMergeOperation.Type\x12\x32\n\nsrc_extent\x18\x02 \x01(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x32\n\ndst_extent\x18\x03 \x01(\x0b\x32\x1e.chromeos_update_engine.Extent\"\x14\n\x04Type\x12\x0c\n\x08\x43OW_COPY\x10\x00\"\xc8\x06\n\x0fPartitionUpdate\x12\x16\n\x0epartition_name\x18\x01 \x02(\t\x12\x17\n\x0frun_postinstall\x18\x02 \x01(\x08\x12\x18\n\x10postinstall_path\x18\x03 \x01(\t\x12\x17\n\x0f\x66ilesystem_type\x18\x04 \x01(\t\x12M\n\x17new_partition_signature\x18\x05 \x03(\x0b\x32,.chromeos_update_engine.Signatures.Signature\x12\x41\n\x12old_partition_info\x18\x06 \x01(\x0b\x32%.chromeos_update_engine.PartitionInfo\x12\x41\n\x12new_partition_info\x18\x07 \x01(\x0b\x32%.chromeos_update_engine.PartitionInfo\x12<\n\noperations\x18\x08 \x03(\x0b\x32(.chromeos_update_engine.InstallOperation\x12\x1c\n\x14postinstall_optional\x18\t \x01(\x08\x12=\n\x15hash_tree_data_extent\x18\n \x01(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x38\n\x10hash_tree_extent\x18\x0b \x01(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x1b\n\x13hash_tree_algorithm\x18\x0c \x01(\t\x12\x16\n\x0ehash_tree_salt\x18\r \x01(\x0c\x12\x37\n\x0f\x66\x65\x63_data_extent\x18\x0e \x01(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x32\n\nfec_extent\x18\x0f \x01(\x0b\x32\x1e.chromeos_update_engine.Extent\x12\x14\n\tfec_roots\x18\x10 \x01(\r:\x01\x32\x12\x0f\n\x07version\x18\x11 \x01(\t\x12\x43\n\x10merge_operations\x18\x12 \x03(\x0b\x32).chromeos_update_engine.CowMergeOperation\x12\x19\n\x11\x65stimate_cow_size\x18\x13 \x01(\x04\"L\n\x15\x44ynamicPartitionGroup\x12\x0c\n\x04name\x18\x01 \x02(\t\x12\x0c\n\x04size\x18\x02 \x01(\x04\x12\x17\n\x0fpartition_names\x18\x03 \x03(\t\"\x89\x01\n\x18\x44ynamicPartitionMetadata\x12=\n\x06groups\x18\x01 \x03(\x0b\x32-.chromeos_update_engine.DynamicPartitionGroup\x12\x18\n\x10snapshot_enabled\x18\x02 \x01(\x08\x12\x14\n\x0cvabc_enabled\x18\x03 \x01(\x08\"\xe9\x06\n\x14\x44\x65ltaArchiveManifest\x12H\n\x12install_operations\x18\x01 \x03(\x0b\x32(.chromeos_update_engine.InstallOperationB\x02\x18\x01\x12O\n\x19kernel_install_operations\x18\x02 \x03(\x0b\x32(.chromeos_update_engine.InstallOperationB\x02\x18\x01\x12\x18\n\nblock_size\x18\x03 \x01(\r:\x04\x34\x30\x39\x36\x12\x19\n\x11signatures_offset\x18\x04 \x01(\x04\x12\x17\n\x0fsignatures_size\x18\x05 \x01(\x04\x12\x42\n\x0fold_kernel_info\x18\x06 \x01(\x0b\x32%.chromeos_update_engine.PartitionInfoB\x02\x18\x01\x12\x42\n\x0fnew_kernel_info\x18\x07 \x01(\x0b\x32%.chromeos_update_engine.PartitionInfoB\x02\x18\x01\x12\x42\n\x0fold_rootfs_info\x18\x08 \x01(\x0b\x32%.chromeos_update_engine.PartitionInfoB\x02\x18\x01\x12\x42\n\x0fnew_rootfs_info\x18\t \x01(\x0b\x32%.chromeos_update_engine.PartitionInfoB\x02\x18\x01\x12=\n\x0eold_image_info\x18\n \x01(\x0b\x32!.chromeos_update_engine.ImageInfoB\x02\x18\x01\x12=\n\x0enew_image_info\x18\x0b \x01(\x0b\x32!.chromeos_update_engine.ImageInfoB\x02\x18\x01\x12\x18\n\rminor_version\x18\x0c \x01(\r:\x01\x30\x12;\n\npartitions\x18\r \x03(\x0b\x32\'.chromeos_update_engine.PartitionUpdate\x12\x15\n\rmax_timestamp\x18\x0e \x01(\x03\x12T\n\x1a\x64ynamic_partition_metadata\x18\x0f \x01(\x0b\x32\x30.chromeos_update_engine.DynamicPartitionMetadata\x12\x16\n\x0epartial_update\x18\x10 \x01(\x08\x42\x02H\x03'
 )
 
 
@@ -28,56 +29,68 @@
   full_name='chromeos_update_engine.InstallOperation.Type',
   filename=None,
   file=DESCRIPTOR,
+  create_key=_descriptor._internal_create_key,
   values=[
     _descriptor.EnumValueDescriptor(
       name='REPLACE', index=0, number=0,
       serialized_options=None,
-      type=None),
+      type=None,
+      create_key=_descriptor._internal_create_key),
     _descriptor.EnumValueDescriptor(
       name='REPLACE_BZ', index=1, number=1,
       serialized_options=None,
-      type=None),
+      type=None,
+      create_key=_descriptor._internal_create_key),
     _descriptor.EnumValueDescriptor(
       name='MOVE', index=2, number=2,
       serialized_options=b'\010\001',
-      type=None),
+      type=None,
+      create_key=_descriptor._internal_create_key),
     _descriptor.EnumValueDescriptor(
       name='BSDIFF', index=3, number=3,
       serialized_options=b'\010\001',
-      type=None),
+      type=None,
+      create_key=_descriptor._internal_create_key),
     _descriptor.EnumValueDescriptor(
       name='SOURCE_COPY', index=4, number=4,
       serialized_options=None,
-      type=None),
+      type=None,
+      create_key=_descriptor._internal_create_key),
     _descriptor.EnumValueDescriptor(
       name='SOURCE_BSDIFF', index=5, number=5,
       serialized_options=None,
-      type=None),
+      type=None,
+      create_key=_descriptor._internal_create_key),
     _descriptor.EnumValueDescriptor(
       name='REPLACE_XZ', index=6, number=8,
       serialized_options=None,
-      type=None),
+      type=None,
+      create_key=_descriptor._internal_create_key),
     _descriptor.EnumValueDescriptor(
       name='ZERO', index=7, number=6,
       serialized_options=None,
-      type=None),
+      type=None,
+      create_key=_descriptor._internal_create_key),
     _descriptor.EnumValueDescriptor(
       name='DISCARD', index=8, number=7,
       serialized_options=None,
-      type=None),
+      type=None,
+      create_key=_descriptor._internal_create_key),
     _descriptor.EnumValueDescriptor(
       name='BROTLI_BSDIFF', index=9, number=10,
       serialized_options=None,
-      type=None),
+      type=None,
+      create_key=_descriptor._internal_create_key),
     _descriptor.EnumValueDescriptor(
       name='PUFFDIFF', index=10, number=9,
       serialized_options=None,
-      type=None),
+      type=None,
+      create_key=_descriptor._internal_create_key),
   ],
   containing_type=None,
   serialized_options=None,
-  serialized_start=750,
-  serialized_end=923,
+  serialized_start=775,
+  serialized_end=948,
 )
 _sym_db.RegisterEnumDescriptor(_INSTALLOPERATION_TYPE)
 
@@ -86,16 +99,18 @@
   full_name='chromeos_update_engine.CowMergeOperation.Type',
   filename=None,
   file=DESCRIPTOR,
+  create_key=_descriptor._internal_create_key,
   values=[
     _descriptor.EnumValueDescriptor(
       name='COW_COPY', index=0, number=0,
       serialized_options=None,
-      type=None),
+      type=None,
+      create_key=_descriptor._internal_create_key),
   ],
   containing_type=None,
   serialized_options=None,
-  serialized_start=1113,
-  serialized_end=1133,
+  serialized_start=1138,
+  serialized_end=1158,
 )
 _sym_db.RegisterEnumDescriptor(_COWMERGEOPERATION_TYPE)
 
@@ -106,6 +121,7 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
+  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='start_block', full_name='chromeos_update_engine.Extent.start_block', index=0,
@@ -113,14 +129,14 @@
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='num_blocks', full_name='chromeos_update_engine.Extent.num_blocks', index=1,
       number=2, type=4, cpp_type=4, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
   ],
   extensions=[
   ],
@@ -144,6 +160,7 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
+  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='version', full_name='chromeos_update_engine.Signatures.Signature.version', index=0,
@@ -151,21 +168,21 @@
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=b'\030\001', file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='data', full_name='chromeos_update_engine.Signatures.Signature.data', index=1,
       number=2, type=12, cpp_type=9, label=1,
       has_default_value=False, default_value=b"",
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='unpadded_signature_size', full_name='chromeos_update_engine.Signatures.Signature.unpadded_signature_size', index=2,
       number=3, type=7, cpp_type=3, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
   ],
   extensions=[
   ],
@@ -188,6 +205,7 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
+  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='signatures', full_name='chromeos_update_engine.Signatures.signatures', index=0,
@@ -195,7 +213,7 @@
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
   ],
   extensions=[
   ],
@@ -219,6 +237,7 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
+  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='size', full_name='chromeos_update_engine.PartitionInfo.size', index=0,
@@ -226,14 +245,14 @@
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='hash', full_name='chromeos_update_engine.PartitionInfo.hash', index=1,
       number=2, type=12, cpp_type=9, label=1,
       has_default_value=False, default_value=b"",
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
   ],
   extensions=[
   ],
@@ -257,6 +276,7 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
+  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='board', full_name='chromeos_update_engine.ImageInfo.board', index=0,
@@ -264,42 +284,42 @@
       has_default_value=False, default_value=b"".decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='key', full_name='chromeos_update_engine.ImageInfo.key', index=1,
       number=2, type=9, cpp_type=9, label=1,
       has_default_value=False, default_value=b"".decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='channel', full_name='chromeos_update_engine.ImageInfo.channel', index=2,
       number=3, type=9, cpp_type=9, label=1,
       has_default_value=False, default_value=b"".decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='version', full_name='chromeos_update_engine.ImageInfo.version', index=3,
       number=4, type=9, cpp_type=9, label=1,
       has_default_value=False, default_value=b"".decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='build_channel', full_name='chromeos_update_engine.ImageInfo.build_channel', index=4,
       number=5, type=9, cpp_type=9, label=1,
       has_default_value=False, default_value=b"".decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='build_version', full_name='chromeos_update_engine.ImageInfo.build_version', index=5,
       number=6, type=9, cpp_type=9, label=1,
       has_default_value=False, default_value=b"".decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
   ],
   extensions=[
   ],
@@ -312,8 +332,8 @@
   extension_ranges=[],
   oneofs=[
   ],
-  serialized_start=307,
-  serialized_end=426,
+  serialized_start=308,
+  serialized_end=451,
 )
 
 
@@ -323,6 +343,7 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
+  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='type', full_name='chromeos_update_engine.InstallOperation.type', index=0,
@@ -330,63 +351,63 @@
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='data_offset', full_name='chromeos_update_engine.InstallOperation.data_offset', index=1,
       number=2, type=4, cpp_type=4, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='data_length', full_name='chromeos_update_engine.InstallOperation.data_length', index=2,
       number=3, type=4, cpp_type=4, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='src_extents', full_name='chromeos_update_engine.InstallOperation.src_extents', index=3,
       number=4, type=11, cpp_type=10, label=3,
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='src_length', full_name='chromeos_update_engine.InstallOperation.src_length', index=4,
       number=5, type=4, cpp_type=4, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='dst_extents', full_name='chromeos_update_engine.InstallOperation.dst_extents', index=5,
       number=6, type=11, cpp_type=10, label=3,
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='dst_length', full_name='chromeos_update_engine.InstallOperation.dst_length', index=6,
       number=7, type=4, cpp_type=4, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='data_sha256_hash', full_name='chromeos_update_engine.InstallOperation.data_sha256_hash', index=7,
       number=8, type=12, cpp_type=9, label=1,
       has_default_value=False, default_value=b"",
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='src_sha256_hash', full_name='chromeos_update_engine.InstallOperation.src_sha256_hash', index=8,
       number=9, type=12, cpp_type=9, label=1,
       has_default_value=False, default_value=b"",
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
   ],
   extensions=[
   ],
@@ -400,8 +421,8 @@
   extension_ranges=[],
   oneofs=[
   ],
-  serialized_start=429,
-  serialized_end=923,
+  serialized_start=454,
+  serialized_end=948,
 )
 
 
@@ -411,6 +432,7 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
+  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='type', full_name='chromeos_update_engine.CowMergeOperation.type', index=0,
@@ -418,21 +440,21 @@
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='src_extent', full_name='chromeos_update_engine.CowMergeOperation.src_extent', index=1,
       number=2, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='dst_extent', full_name='chromeos_update_engine.CowMergeOperation.dst_extent', index=2,
       number=3, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
   ],
   extensions=[
   ],
@@ -446,8 +468,8 @@
   extension_ranges=[],
   oneofs=[
   ],
-  serialized_start=926,
-  serialized_end=1133,
+  serialized_start=951,
+  serialized_end=1158,
 )
 
 
@@ -457,6 +479,7 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
+  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='partition_name', full_name='chromeos_update_engine.PartitionUpdate.partition_name', index=0,
@@ -464,133 +487,133 @@
       has_default_value=False, default_value=b"".decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='run_postinstall', full_name='chromeos_update_engine.PartitionUpdate.run_postinstall', index=1,
       number=2, type=8, cpp_type=7, label=1,
       has_default_value=False, default_value=False,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='postinstall_path', full_name='chromeos_update_engine.PartitionUpdate.postinstall_path', index=2,
       number=3, type=9, cpp_type=9, label=1,
       has_default_value=False, default_value=b"".decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='filesystem_type', full_name='chromeos_update_engine.PartitionUpdate.filesystem_type', index=3,
       number=4, type=9, cpp_type=9, label=1,
       has_default_value=False, default_value=b"".decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='new_partition_signature', full_name='chromeos_update_engine.PartitionUpdate.new_partition_signature', index=4,
       number=5, type=11, cpp_type=10, label=3,
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='old_partition_info', full_name='chromeos_update_engine.PartitionUpdate.old_partition_info', index=5,
       number=6, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='new_partition_info', full_name='chromeos_update_engine.PartitionUpdate.new_partition_info', index=6,
       number=7, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='operations', full_name='chromeos_update_engine.PartitionUpdate.operations', index=7,
       number=8, type=11, cpp_type=10, label=3,
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='postinstall_optional', full_name='chromeos_update_engine.PartitionUpdate.postinstall_optional', index=8,
       number=9, type=8, cpp_type=7, label=1,
       has_default_value=False, default_value=False,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='hash_tree_data_extent', full_name='chromeos_update_engine.PartitionUpdate.hash_tree_data_extent', index=9,
       number=10, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='hash_tree_extent', full_name='chromeos_update_engine.PartitionUpdate.hash_tree_extent', index=10,
       number=11, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='hash_tree_algorithm', full_name='chromeos_update_engine.PartitionUpdate.hash_tree_algorithm', index=11,
       number=12, type=9, cpp_type=9, label=1,
       has_default_value=False, default_value=b"".decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='hash_tree_salt', full_name='chromeos_update_engine.PartitionUpdate.hash_tree_salt', index=12,
       number=13, type=12, cpp_type=9, label=1,
       has_default_value=False, default_value=b"",
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='fec_data_extent', full_name='chromeos_update_engine.PartitionUpdate.fec_data_extent', index=13,
       number=14, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='fec_extent', full_name='chromeos_update_engine.PartitionUpdate.fec_extent', index=14,
       number=15, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='fec_roots', full_name='chromeos_update_engine.PartitionUpdate.fec_roots', index=15,
       number=16, type=13, cpp_type=3, label=1,
       has_default_value=True, default_value=2,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='version', full_name='chromeos_update_engine.PartitionUpdate.version', index=16,
       number=17, type=9, cpp_type=9, label=1,
       has_default_value=False, default_value=b"".decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='merge_operations', full_name='chromeos_update_engine.PartitionUpdate.merge_operations', index=17,
       number=18, type=11, cpp_type=10, label=3,
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='estimate_cow_size', full_name='chromeos_update_engine.PartitionUpdate.estimate_cow_size', index=18,
       number=19, type=4, cpp_type=4, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
   ],
   extensions=[
   ],
@@ -603,8 +626,8 @@
   extension_ranges=[],
   oneofs=[
   ],
-  serialized_start=1136,
-  serialized_end=1976,
+  serialized_start=1161,
+  serialized_end=2001,
 )
 
 
@@ -614,6 +637,7 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
+  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='name', full_name='chromeos_update_engine.DynamicPartitionGroup.name', index=0,
@@ -621,21 +645,21 @@
       has_default_value=False, default_value=b"".decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='size', full_name='chromeos_update_engine.DynamicPartitionGroup.size', index=1,
       number=2, type=4, cpp_type=4, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='partition_names', full_name='chromeos_update_engine.DynamicPartitionGroup.partition_names', index=2,
       number=3, type=9, cpp_type=9, label=3,
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
   ],
   extensions=[
   ],
@@ -648,8 +672,8 @@
   extension_ranges=[],
   oneofs=[
   ],
-  serialized_start=1978,
-  serialized_end=2054,
+  serialized_start=2003,
+  serialized_end=2079,
 )
 
 
@@ -659,6 +683,7 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
+  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='groups', full_name='chromeos_update_engine.DynamicPartitionMetadata.groups', index=0,
@@ -666,14 +691,21 @@
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='snapshot_enabled', full_name='chromeos_update_engine.DynamicPartitionMetadata.snapshot_enabled', index=1,
       number=2, type=8, cpp_type=7, label=1,
       has_default_value=False, default_value=False,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+    _descriptor.FieldDescriptor(
+      name='vabc_enabled', full_name='chromeos_update_engine.DynamicPartitionMetadata.vabc_enabled', index=2,
+      number=3, type=8, cpp_type=7, label=1,
+      has_default_value=False, default_value=False,
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
   ],
   extensions=[
   ],
@@ -686,8 +718,8 @@
   extension_ranges=[],
   oneofs=[
   ],
-  serialized_start=2056,
-  serialized_end=2171,
+  serialized_start=2082,
+  serialized_end=2219,
 )
 
 
@@ -697,6 +729,7 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
+  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='install_operations', full_name='chromeos_update_engine.DeltaArchiveManifest.install_operations', index=0,
@@ -704,112 +737,112 @@
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=b'\030\001', file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='kernel_install_operations', full_name='chromeos_update_engine.DeltaArchiveManifest.kernel_install_operations', index=1,
       number=2, type=11, cpp_type=10, label=3,
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=b'\030\001', file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='block_size', full_name='chromeos_update_engine.DeltaArchiveManifest.block_size', index=2,
       number=3, type=13, cpp_type=3, label=1,
       has_default_value=True, default_value=4096,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='signatures_offset', full_name='chromeos_update_engine.DeltaArchiveManifest.signatures_offset', index=3,
       number=4, type=4, cpp_type=4, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='signatures_size', full_name='chromeos_update_engine.DeltaArchiveManifest.signatures_size', index=4,
       number=5, type=4, cpp_type=4, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='old_kernel_info', full_name='chromeos_update_engine.DeltaArchiveManifest.old_kernel_info', index=5,
       number=6, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=b'\030\001', file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='new_kernel_info', full_name='chromeos_update_engine.DeltaArchiveManifest.new_kernel_info', index=6,
       number=7, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=b'\030\001', file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='old_rootfs_info', full_name='chromeos_update_engine.DeltaArchiveManifest.old_rootfs_info', index=7,
       number=8, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=b'\030\001', file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='new_rootfs_info', full_name='chromeos_update_engine.DeltaArchiveManifest.new_rootfs_info', index=8,
       number=9, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=b'\030\001', file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='old_image_info', full_name='chromeos_update_engine.DeltaArchiveManifest.old_image_info', index=9,
       number=10, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='new_image_info', full_name='chromeos_update_engine.DeltaArchiveManifest.new_image_info', index=10,
       number=11, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=b'\030\001', file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='minor_version', full_name='chromeos_update_engine.DeltaArchiveManifest.minor_version', index=11,
       number=12, type=13, cpp_type=3, label=1,
       has_default_value=True, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='partitions', full_name='chromeos_update_engine.DeltaArchiveManifest.partitions', index=12,
       number=13, type=11, cpp_type=10, label=3,
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='max_timestamp', full_name='chromeos_update_engine.DeltaArchiveManifest.max_timestamp', index=13,
       number=14, type=3, cpp_type=2, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='dynamic_partition_metadata', full_name='chromeos_update_engine.DeltaArchiveManifest.dynamic_partition_metadata', index=14,
       number=15, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
     _descriptor.FieldDescriptor(
       name='partial_update', full_name='chromeos_update_engine.DeltaArchiveManifest.partial_update', index=15,
       number=16, type=8, cpp_type=7, label=1,
       has_default_value=False, default_value=False,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR),
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
   ],
   extensions=[
   ],
@@ -822,8 +855,8 @@
   extension_ranges=[],
   oneofs=[
   ],
-  serialized_start=2174,
-  serialized_end=3039,
+  serialized_start=2222,
+  serialized_end=3095,
 )
 
 _SIGNATURES_SIGNATURE.containing_type = _SIGNATURES
@@ -949,6 +982,12 @@
 
 DESCRIPTOR._options = None
 _SIGNATURES_SIGNATURE.fields_by_name['version']._options = None
+_IMAGEINFO.fields_by_name['board']._options = None
+_IMAGEINFO.fields_by_name['key']._options = None
+_IMAGEINFO.fields_by_name['channel']._options = None
+_IMAGEINFO.fields_by_name['version']._options = None
+_IMAGEINFO.fields_by_name['build_channel']._options = None
+_IMAGEINFO.fields_by_name['build_version']._options = None
 _INSTALLOPERATION_TYPE.values_by_name["MOVE"]._options = None
 _INSTALLOPERATION_TYPE.values_by_name["BSDIFF"]._options = None
 _DELTAARCHIVEMANIFEST.fields_by_name['install_operations']._options = None
@@ -957,4 +996,6 @@
 _DELTAARCHIVEMANIFEST.fields_by_name['new_kernel_info']._options = None
 _DELTAARCHIVEMANIFEST.fields_by_name['old_rootfs_info']._options = None
 _DELTAARCHIVEMANIFEST.fields_by_name['new_rootfs_info']._options = None
+_DELTAARCHIVEMANIFEST.fields_by_name['old_image_info']._options = None
+_DELTAARCHIVEMANIFEST.fields_by_name['new_image_info']._options = None
 # @@protoc_insertion_point(module_scope)
diff --git a/update_metadata.proto b/update_metadata.proto
index 452b89d..c57e4c1 100644
--- a/update_metadata.proto
+++ b/update_metadata.proto
@@ -348,6 +348,12 @@
   // partitions if possible. If this is unset, the update_engine daemon MUST
   // NOT create snapshots for dynamic partitions.
   optional bool snapshot_enabled = 2;
+
+  // If this is set to false, update_engine should not use VABC regardless. If
+  // this is set to true, update_engine may choose to use VABC if device
+  // supports it, but not guaranteed.
+  // VABC stands for Virtual AB Compression
+  optional bool vabc_enabled = 3;
 }
 
 message DeltaArchiveManifest {