build: releasetools: Support transparent compression

Change-Id: I339fe8dbf287ce7c88e133a5b3f5c502dc56dd3b
diff --git a/core/Makefile b/core/Makefile
index b7b233f..44a19a3 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -735,6 +735,10 @@
   INTERNAL_USERIMAGES_SPARSE_EXT_FLAG := -s
 endif
 
+ifneq ($(TARGET_TRANSPARENT_COMPRESSION_METHOD),)
+  INTERNAL_TRANSPARENT_COMPRESSION_METHOD := $(TARGET_TRANSPARENT_COMPRESSION_METHOD)
+endif
+
 ifeq ($(INTERNAL_USERIMAGES_USE_EXT),true)
 INTERNAL_USERIMAGES_DEPS := $(SIMG2IMG)
 INTERNAL_USERIMAGES_DEPS += $(MKEXTUSERIMG) $(MAKE_EXT4FS) $(E2FSCK)
@@ -770,6 +774,7 @@
 $(if $(BOARD_OEMIMAGE_PARTITION_SIZE),$(hide) echo "oem_size=$(BOARD_OEMIMAGE_PARTITION_SIZE)" >> $(1))
 $(if $(BOARD_OEMIMAGE_JOURNAL_SIZE),$(hide) echo "oem_journal_size=$(BOARD_OEMIMAGE_JOURNAL_SIZE)" >> $(1))
 $(if $(INTERNAL_USERIMAGES_SPARSE_EXT_FLAG),$(hide) echo "extfs_sparse_flag=$(INTERNAL_USERIMAGES_SPARSE_EXT_FLAG)" >> $(1))
+$(if $(INTERNAL_TRANSPARENT_COMPRESSION_METHOD),$(hide) echo "transparent_compression_method=$(INTERNAL_TRANSPARENT_COMPRESSION_METHOD)" >> $(1))
 $(if $(mkyaffs2_extra_flags),$(hide) echo "mkyaffs2_extra_flags=$(mkyaffs2_extra_flags)" >> $(1))
 $(hide) echo "selinux_fc=$(SELINUX_FC)" >> $(1)
 $(if $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_SUPPORTS_VERITY),$(hide) echo "verity=$(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_SUPPORTS_VERITY)" >> $(1))
diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index 0082a64..29ccd62 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -248,6 +248,8 @@
       build_command.extend(["-C", fs_config])
     if block_list is not None:
       build_command.extend(["-B", block_list])
+    if "transparent_compression_method" in prop_dict:
+      build_command.extend(["-M", prop_dict["transparent_compression_method"]])
     if fc_config is not None:
       build_command.append(fc_config)
     elif "selinux_fc" in prop_dict:
@@ -312,7 +314,8 @@
       "skip_fsck",
       "verity",
       "verity_key",
-      "verity_signer_cmd"
+      "verity_signer_cmd",
+      "transparent_compression_method"
       )
   for p in common_props:
     copy_prop(p, p)