[Reland] Refactor WebappRegistry into a singleton instance.

chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationService.java

Index: chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationService.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationService.java b/chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationService.java
index 4b3eed1e42f5228c0b6222a9cef9abfbfe85c03f..176e45f0c1971127f3ff9a03fc8bf119f57f6ffd 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationService.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationService.java
@@ -8,12 +8,14 @@ import android.app.IntentService;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
+import android.os.StrictMode;
 import android.util.Log;
 
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.annotations.SuppressFBWarnings;
 import org.chromium.base.library_loader.ProcessInitException;
 import org.chromium.chrome.browser.init.ChromeBrowserInitializer;
+import org.chromium.chrome.browser.webapps.WebappRegistry;
 
 /**
  * The Notification service receives intents fired as responses to user actions issued on Android
@@ -76,6 +78,18 @@ public class NotificationService extends IntentService {
         try {
             ChromeBrowserInitializer.getInstance(this).handleSynchronousStartup();
 
+            // Warm up the WebappRegistry, as we need to check if this notification should launch a
+            // standalone web app. This no-ops if the registry is already initialized and warmed,
+            // but triggers a strict mode violation otherwise (i.e. the browser isn't running).
+            // Temporarily disable strict mode to work around the violation.
+            StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads();
+            try {
+                WebappRegistry.getInstance();
+                WebappRegistry.warmUpSharedPrefs();
+            } finally {
+                StrictMode.setThreadPolicy(oldPolicy);
+            }
+
             // Now that the browser process is initialized, we pass forward the call to the
             // NotificationPlatformBridge which will take care of delivering the appropriate events.
             if (!NotificationPlatformBridge.dispatchNotificationEvent(intent)) {