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..f876ad5170805e56a4237547969f63dcd7dd4da3 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.WebApkInstallClientDelegate;
 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 WebApkInstallClientDelegate that can talk to Play Store to
+     *  install WebAPKs.
+     */
+    public WebApkInstallClientDelegate createWebApkInstallClientDelegate() {
+        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.