Request upgraded WebAPK from WebAPK server if the ShellAPK version changes
The ShellAPK version is the version of the source code in
//chrome/android/webapk/shell_apk
This CL also makes WebApkUpdateManager get the WebAPK's <meta-data> from the
Android Manifest and pass it to ManifestUpgradeDetector. Repeatedly requesting
the <meta-data> from the PackageManager takes 0.5ms on a Nexus 5.
BUG=
624834
Committed:
https://crrev.com/eab4e851447a299a36458474d824b0ed569db55f
Cr-Commit-Position: refs/heads/master@{#415079}