[WebAPKs] Make WebAPK update flow more sensible

chrome/android/webapk/shell_apk/shell_apk_version.gni

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Must be incremented whenever code in //chrome/android/webapk/shell_apk
-# (including AndroidManifest.xml) is updated.
-shell_apk_version = 3
+# (including AndroidManifest.xml) is updated. This version should be incremented
+# prior to uploading a new ShellAPK to the WebAPK Minting Server.
+template_shell_apk_version = 3

[Xi Han, 2017/04/24 13:41:13]

How about |shell_apk_template_version_in_Chrome|?

[pkotwicz, 2017/04/25 01:15:31]

I have renamed this to shell_apk_template_version_on_server

[Xi Han, 2017/04/25 13:58:24]

The template is first updated in Chrome, and then on server, so we shouldn't
name it to |version_on_server|. My suggestion is to make this variable mean "the
current version of the template that is baked in Chrome" and let it reflect any
change of the template in Chrome. 

[pkotwicz, 2017/04/25 22:29:33]

I have reverted to the previous variable name

This variable is not "the current version which is baked into Chrome". In
particular, it does not affect Chrome.apk It affects WebApk.apk A script which
is part of the "official builders" extracts the .dex file from the compiled
WebApk.apk and uploads it to Google Cloud Storage.

Glenn's magical script to update the ShellAPK takes information from Google
Cloud Storage

[Xi Han, 2017/04/26 01:08:15]

Thanks for the explanation:)

+
+# The ShellAPK version expected by the browser. Chrome will try to update the
+# WebAPK if the WebAPK's ShellAPK version is less than
+# |expected_shell_apk_version|. The version should be incremented after a new
+# ShellAPK has been uploaded to the WebAPK Minting Server.
+expected_shell_apk_version = 3

[Xi Han, 2017/04/24 13:41:13]

Can we rename it to |shell_apk_template_version_on_server|?

[pkotwicz, 2017/04/25 01:15:31]

I have renamed this to shell_apk_version_expected_by_chrome

[Xi Han, 2017/04/25 13:58:23]

I would prefer your previous version than this one. My suggestion is different
than the one that you choose. I just notice that the naming that I suggested
doesn't match the description. The description could change to something like:
"The ShellAPK version that Chrome believes the WebAPK Minting Server has. Chrome
will try to update the WebAPK ...."

If you don't like my suggestion, please revert to your previous version for both
namings. It is up to you:)