Chrome talks to Play to install WebAPKs.

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstallClientDelegate.java

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstallClientDelegate.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstallClientDelegate.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstallClientDelegate.java
new file mode 100644
index 0000000000000000000000000000000000000000..635cdae9907de1c11b02237f114cad58bf29ab00
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstallClientDelegate.java
@@ -0,0 +1,30 @@
+// 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.
+
+package org.chromium.chrome.browser.webapps;
+
+import org.chromium.base.Callback;
+
+/**
+ * Define an interface of client delegate which binds to Phonesky's PlayInstallService to install
+ * WebAPKs.

[pkotwicz, 2016/12/02 02:23:59]

How about: "Defines an interface for installing WebAPKs via Google Play."

- Phonesky is the Google-internal name for the Google-Play-Client. We shouldn't
use it in external facing code.
- Binding to PlayInstallService is an implementation detail

[Xi Han, 2016/12/02 20:45:36]

Done.

+ */

[pkotwicz, 2016/12/02 02:23:59]

How about: GooglePlayWebApkInstallDelegate

ClientDelegate is more complicated than needed.
(Yes I know that this class talks to the Google Play client)

I remember that someone in the Chrome team in our office really wanted to get
some complicated named classes into the code base. This was back when we had a
class named RenderWidgetHostViewViews

[Xi Han, 2016/12/02 20:45:36]

Done.

+public interface WebApkInstallClientDelegate {
+    /**
+     * Binds to Phonesky's PlayInstallService and installs WebAPKs asynchronously.

[pkotwicz, 2016/12/02 02:23:59]

How about: "Uses Google Play to install WebAPK asynchronously."

[Xi Han, 2016/12/02 20:45:36]

Done.

+     * @param packageName The package name of WebAPK to install.
+     * @param version The version of WebAPK to install.
+     * @param title The title of the WebAPK to display during installation.
+     * @param wamToken The token from WebAPK Minter Server.

[pkotwicz, 2016/12/02 02:23:59]

Nit: wamToken -> token

People outside of our team do not know the meaning of the "wam" acronym

(Some people might be from the city of Wam in Pakistan though)

[Xi Han, 2016/12/02 20:45:36]

Done.

+     * @return True if either successfully binded to the PlayInstallService or the install was
+     *         started. A "true" return value does not guarantee that the install succeeds.

[pkotwicz, 2016/12/02 02:23:59]

How about: True if the install was started. A "true" value does not...

[Xi Han, 2016/12/02 20:45:36]

Well, I think we can count the "bind to the PlayInstallService" as the install
was started. I listed that case here because for the first request, we need to
bind to the service first, and then execute an async task to call the install
API. So the direct return value means whether we can bind to the service
successfully, not call to the install API successfully.

+     */
+    boolean installAsync(String packageName, int version, String title, String wamToken,
+            Callback<Boolean> callback);
+
+    /**
+     * Destroy the delegate, cleaning up any open hooks.
+     */
+    void reset();

[pkotwicz, 2016/12/02 02:23:59]

reset() does not seem to be called by any of the open source code. Can we remove
it from the interface?

[Xi Han, 2016/12/02 20:45:36]

Yes, that is what I find when I am polishing the internal CL. Removed.

+}