Change EAS authenticator's label according to the vendor policy.

Our original plan was to disable both authenticators by default, and enable
one of then on boot.  However, it turned out existing exchange accounts will
be removed if there's no enabled authenticators for the account type.
So, instead, in this patch we initially enable only the default one, and switch
to the other one on boot if the vendor policy indicates so.

(If a device has a vendor policy apk, it should also have the email app
preloaded, so changing the label at boot time isn't too late.)

Bug: 2382710
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index caf9592..13210ef 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -207,6 +207,15 @@
             </intent-filter>
         </receiver>
         
+        <receiver
+            android:name=".OneTimeInitializer"
+            android:enabled="true"
+            >
+            <intent-filter>
+                <action android:name="android.intent.action.BOOT_COMPLETED" />
+            </intent-filter>
+        </receiver>
+
         <service
             android:name=".service.MailService"
             android:enabled="false"
@@ -243,12 +252,35 @@
         </service>
 
         <!--Required stanza to register the EasAuthenticatorService with AccountManager -->
-        <service android:name=".service.EasAuthenticatorService" android:exported="true">
+        <service
+            android:name=".service.EasAuthenticatorService"
+            android:exported="true"
+            android:enabled="true"
+            >
             <intent-filter>
                 <action android:name="android.accounts.AccountAuthenticator" />
             </intent-filter>
-            <meta-data android:name="android.accounts.AccountAuthenticator"
-                       android:resource="@xml/authenticator" />
+            <meta-data
+                android:name="android.accounts.AccountAuthenticator"
+                android:resource="@xml/authenticator"
+                />
+        </service>
+        <!--
+            EasAuthenticatorService with the altenative label.  Disabled by default,
+            and OneTimeInitializer enables it if the vendor policy tells so.
+        -->
+        <service
+            android:name=".service.EasAuthenticatorServiceAlternate"
+            android:exported="true"
+            android:enabled="false"
+            >
+            <intent-filter>
+                <action android:name="android.accounts.AccountAuthenticator" />
+            </intent-filter>
+            <meta-data
+                android:name="android.accounts.AccountAuthenticator"
+                android:resource="@xml/authenticator_alternate"
+                />
         </service>
 
         <provider