store images in target-files

Store sparse images in the target-files, and use those (when they're
available) for building block OTAs.

- New script add_img_to_target_files is added to make the images and
  add them to the IMAGES/ subdir in the target-files.  It gets run
  from the Makefile when building a target-files.

- img_from_target_files becomes mostly vestigial: it creates the
  img.zip by just copying the images out of the target-files.  (It
  still knows how to build images for use on older target-files.)

- ota_from_target_files uses images from the target-files in
  preference to rebuilding images from the source files.

- sign_apk_target_files builds images and includes them in its output
  target files (even if the input target-files didn't have them).

Bug: 16488065
Change-Id: I444e0d722d636978209467ffc01750a585c6db75
diff --git a/core/Makefile b/core/Makefile
index 36d53e1..c556ed7 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1415,6 +1415,7 @@
 	$(hide) zipinfo -1 $@ | awk 'BEGIN { FS="BOOT/RAMDISK/" } /^BOOT\/RAMDISK\// {print $$2}' | $(HOST_OUT_EXECUTABLES)/fs_config -C -S $(SELINUX_FC) > $(zip_root)/META/boot_filesystem_config.txt
 	$(hide) zipinfo -1 $@ | awk 'BEGIN { FS="RECOVERY/RAMDISK/" } /^RECOVERY\/RAMDISK\// {print $$2}' | $(HOST_OUT_EXECUTABLES)/fs_config -C -S $(SELINUX_FC) > $(zip_root)/META/recovery_filesystem_config.txt
 	$(hide) (cd $(zip_root) && zip -q ../$(notdir $@) META/*filesystem_config.txt)
+	$(hide) ./build/tools/releasetools/add_img_to_target_files $@
 
 .PHONY: target-files-package
 target-files-package: $(BUILT_TARGET_FILES_PACKAGE)