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..6c443954ee209c052af50ade2ed2f226aa123171
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstallClientDelegate.java
@@ -0,0 +1,38 @@
+// 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 android.os.Bundle;
+
+/**
+ * Binds to Phonesky's PlayInstallService to install WebAPKs.
+ */
+public abstract class WebApkInstallClientDelegate {
+    /**
+     * Class to inform when the installation was either completed or failed.
+     */
+    public interface Observer {
+        /**
+         * Called when the installation status changed.
+         * @param success Whether the installation succeeded.
+         */
+        public void onInstallStateChanged(boolean success);
+    }
+
+    /**
+     * Binds to Phonesky's PlayInstallService and installs WebAPKs asynchronously.
+     * @param installPackage The package name of WebAPK to install.
+     * @param installOptions The data required by the installation.
+     * @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.
+     */
+    public abstract boolean installAsync(Observer observer, String installPackage,
+            Bundle installOptions);
+
+    /**
+     * Destroy the delegate, cleaning up any open hooks.
+     */
+    public abstract void reset();
+}