[components] Closes mozilla-mobile/android-components#1504: Add suppo…

…rt for alert popup in WebView.

X-Channel-Revision: [main] mozilla-mobile/android-components@cf522a7
X-Channel-Revision: [main] mozilla-mobile/fenix@20b25d7
X-Channel-Revision: [main] mozilla-mobile/focus-android@29486b8
X-Channel-Converted-Revision: [ac-prep] mozilla-mobile/firefox-android@b1ab769

_meta/mozilla-mobile-firefox-android.json

@@ -1,6 +1,6 @@
 {
   "name": "mozilla-mobile/firefox-android",
   "revs": {
-    "ac-prep": "837f67c9c56bc49009747dc14b2573fe245b48c4"
+    "ac-prep": "b1ab769c03af21f05c3a934d5cb71deed2e66997"
   }
 }

mozilla-mobile/android-components/components/browser/engine-system/src/main/res/values/strings.xml

@@ -1,8 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
-    <string name="pref_key_privacy_block_ads" translatable="false"><xliff:g id="preference_key">pref_privacy_block_ads</xliff:g></string>
-    <string name="pref_key_privacy_block_analytics" translatable="false"><xliff:g id="preference_key">pref_privacy_block_analytics</xliff:g></string>
-    <string name="pref_key_privacy_block_social" translatable="false"><xliff:g id="preference_key">pref_privacy_block_social</xliff:g></string>
-    <string name="pref_key_privacy_block_other" translatable="false"><xliff:g id="preference_key">pref_privacy_block_other</xliff:g></string>
-    <string name="pref_key_performance_block_webfonts" translatable="false"><xliff:g id="preference_key">pref_performance_block_webfonts</xliff:g></string>
+<resources>
+    <!-- Text for a title dialog on web page. -->
+    <string name="mozac_browser_engine_system_alert_title">The page at %1$s says:</string>
 </resources>