[Android WebAPK] Change WebAPK update into two phases
This CL splits WebAPK updates into two phases:
Phase #1: Compute the proto to send to the WebAPK Minting Server
Phase #2: Send the proto to send to the WebAPK Minting Server and talk to
Google Play
Phase #1 puts the data needed to do an update into an easily serializable
format. This enables a follow up CL to put the output of Phase #1 into a
org.chromium.components.background_task_scheduler.TaskInfo os.Bundle for use
with BackgroundTaskScheduler
BUG=
713655
Review-Url:
https://codereview.chromium.org/2933783002
Cr-Commit-Position: refs/heads/master@{#480255}
Committed:
https://chromium.googlesource.com/chromium/src/+/9940e1d1afe38894e862a18d605b1a64ecb4c2c2