Add a library function for performing a cow dry run

During OTA generation, delta_generator will perform a dry run of VABC
OTA by convert install ops to cow ops and apply them to a cow writer.
This code can be re-used by cow_converter, which is a util for
converting OTA payload to COW image.

Since the conversion happens at generation time, we will have access
to both the source and target images. We can just read data from target
image and write to the cow, no need to actually do
bsdiff/decompression/puffdiff. Therefore we add some utility functions
for writing COW with target image, these functions operate under
different assumptions than update_engine on android devices.

Test: th
Change-Id: I9ab91918c8ee6773bdab04ecbf654e33b7a7d827

0 files changed, 0 insertions, 0 deletions