Chrome talks to Play to install WebAPKs.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/DeferredStartupHandler.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/DeferredStartupHandler.java b/chrome/android/java/src/org/chromium/chrome/browser/DeferredStartupHandler.java
index 7ad77580f366fc2086989e3f2977bc33ccb72788..78d51044f76f1021d336c4afe5d437bcad5fef24 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/DeferredStartupHandler.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/DeferredStartupHandler.java
@@ -46,6 +46,7 @@ import org.chromium.chrome.browser.preferences.ChromePreferenceManager;
 import org.chromium.chrome.browser.preferences.privacy.PrivacyPreferencesManager;
 import org.chromium.chrome.browser.share.ShareHelper;
 import org.chromium.chrome.browser.webapps.ChromeWebApkHost;
+import org.chromium.chrome.browser.webapps.WebApkInstaller;
 import org.chromium.chrome.browser.webapps.WebApkVersionManager;
 import org.chromium.chrome.browser.webapps.WebappRegistry;
 import org.chromium.components.minidump_uploader.CrashFileManager;
@@ -271,6 +272,12 @@ public class DeferredStartupHandler {
 
                     if (ChromeWebApkHost.isEnabled()) {
                         WebApkVersionManager.updateWebApksIfNeeded();
+                        if (ChromeWebApkHost.canUseGooglePlayToInstallWebApk()) {

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

Shouldn't this be called prior to WebApkVersionManager#updateWebApksIfNeeded()

I know that it does not matter because
WebApkVersionManager#updateWebApksIfNeeded() is asynchronous but
WebApkVersionManager#updateWebApksIfNeeded() might need to use the
GooglePlayWebApkInstallDelegate

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

Hmm, I don't think WebApkVersionManager#updateWebApksIfNeeded() needs
GooglePlayWebApkInstallDelegate, since it is used to extract runtime dex but not
really "update" any WebAPK. I am ok to call it first, but the order doesn't
matter.

+                            ChromeApplication application =
+                                    (ChromeApplication) ContextUtils.getApplicationContext();

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

Shoudn't you use mAppContext?

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

Done.

+                            WebApkInstaller.setGooglePlayWebApkInstallDelegate(
+                                    application.createGooglePlayWebApkInstallDelegate());
+                        }
                     }
 
                     removeSnapshotDatabase();