Add com.google.ar.core metadata tag

Remove tools:replace from AndroidManifest.xml
This appears unnecessary and may be causing issues.

Bug: 845517
Change-Id: I913b80edba632b1afcc3836eb357ea9ab7905a27
Reviewed-on: https://chromium-review.googlesource.com/1069264Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Commit-Queue: Max Rebuschatis <lincolnfrog@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560998}

chrome/android/java/AndroidManifest.xml

@@ -163,12 +163,13 @@ by a child template that "extends" this file.
 
         {% if enable_arcore %}
         <!-- ARCore APK integration -->
-        <meta-data tools:replace="android:value"
-            android:name="com.google.ar.core.min_apk_version"
-            android:value="180226000"/>
+        <!-- This tag indicates that this application optionally uses ARCore. -->
+        <meta-data android:name="com.google.ar.core" android:value="optional" />
         <!-- This value referes to ARCore 1.1.
              This value should be updated when ARCore features require
              a newer version of the ARCore SDK. -->
+        <meta-data android:name="com.google.ar.core.min_apk_version"
+            android:value="180226000"/>
         {% endif %}
 
         <!-- Note: All activities directly or indirectly derived from ChromeActivity