From d6c5a30cebc3dfbcfdeaa10e864a2fd6abc71642 Mon Sep 17 00:00:00 2001
From: "Torne (Richard Coles)" <torne@google.com>
Date: Tue, 28 May 2019 16:02:19 -0400
Subject: [PATCH] Always re-enable the fallback WebView if needed.

If there's no valid WebView implementation at boot time, attempt to
re-enable the fallback package, even if we already did the one-time
migration from an earlier OS version.

This may help to ensure devices don't end up with no WebView if
something went wrong with the migration.

Bug: 132815849
Test: manual
Change-Id: I9c9cf634ea0de9b52a27d4c1100d95fad6047b05
---
 .../server/webkit/WebViewUpdateServiceImpl.java  | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/services/core/java/com/android/server/webkit/WebViewUpdateServiceImpl.java b/services/core/java/com/android/server/webkit/WebViewUpdateServiceImpl.java
index 165055ac828c6..11fd7953e08f5 100644
--- a/services/core/java/com/android/server/webkit/WebViewUpdateServiceImpl.java
+++ b/services/core/java/com/android/server/webkit/WebViewUpdateServiceImpl.java
@@ -82,6 +82,22 @@ public class WebViewUpdateServiceImpl {
     void prepareWebViewInSystemServer() {
         migrateFallbackStateOnBoot();
         mWebViewUpdater.prepareWebViewInSystemServer();
+        if (getCurrentWebViewPackage() == null) {
+            // We didn't find a valid WebView implementation. Try explicitly re-enabling the
+            // fallback package for all users in case it was disabled, even if we already did the
+            // one-time migration before. If this actually changes the state, WebViewUpdater will
+            // see the PackageManager broadcast shortly and try again.
+            WebViewProviderInfo[] webviewProviders = mSystemInterface.getWebViewPackages();
+            WebViewProviderInfo fallbackProvider = getFallbackProvider(webviewProviders);
+            if (fallbackProvider != null) {
+                Slog.w(TAG, "No valid provider, trying to enable " + fallbackProvider.packageName);
+                mSystemInterface.enablePackageForAllUsers(mContext, fallbackProvider.packageName,
+                                                          true);
+            } else {
+                Slog.e(TAG, "No valid provider and no fallback available.");
+            }
+        }
+
         boolean multiProcessEnabled = isMultiProcessEnabled();
         mSystemInterface.notifyZygote(multiProcessEnabled);
         if (multiProcessEnabled) {