Chrome talks to Play to install WebAPKs.

chrome/android/java/src/org/chromium/chrome/browser/ChromeApplication.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ChromeApplication.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ChromeApplication.java b/chrome/android/java/src/org/chromium/chrome/browser/ChromeApplication.java
index d28f6f49918a13151b85bfea9ebd9c83502b6606..06e92ef1cdb3edcec129e629f75ea1587ac6c8ec 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ChromeApplication.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ChromeApplication.java
@@ -60,6 +60,7 @@ import org.chromium.chrome.browser.tabmodel.document.ActivityDelegateImpl;
 import org.chromium.chrome.browser.tabmodel.document.DocumentTabModelSelector;
 import org.chromium.chrome.browser.tabmodel.document.StorageDelegate;
 import org.chromium.chrome.browser.tabmodel.document.TabDelegate;
+import org.chromium.chrome.browser.webapps.GooglePlayWebApkInstallDelegate;
 import org.chromium.components.signin.AccountManagerDelegate;
 import org.chromium.components.signin.SystemAccountManagerDelegate;
 import org.chromium.content.app.ContentApplication;
@@ -392,7 +393,15 @@ public class ChromeApplication extends ContentApplication {
     }
 
     /**
-     * Returns the Singleton instance of the DocumentTabModelSelector.
+     * Returns an instance of the GooglePlayWebApkInstallDelegate that can talk to Google Play to
+     * install WebAPKs.
+     */

[pkotwicz, 2016/12/02 22:27:04]

How about: "Creates an instance of GooglePlayWebApkInstallDelegate."

Mentioning that GooglePlayWebApkInstallDelegate talks to Google Play is
redundant

[Xi Han, 2016/12/05 17:27:54]

Done.

+    public GooglePlayWebApkInstallDelegate createGooglePlayWebApkInstallDelegate() {
+        return null;
+    }
+
+    /**
+     * Returns the singleton instance of the DocumentTabModelSelector.
      * TODO(dfalcantara): Find a better place for this once we differentiate between activity and
      *                    application-level TabModelSelectors.
      * @return The DocumentTabModelSelector for the application.