Explicitly export content providers

In a future version of Android, the default value for
<provider android:exported> will change from true to false.
Explicitly set android:exported="true"

Bug: 3306452
Change-Id: Ifeadde3495d249e27bd19e0ae573b8c85b750948
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index c0dc9c1..d15b20b 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -29,17 +29,20 @@
 
         <provider android:name="TelephonyProvider"
                   android:authorities="telephony"
+                  android:exported="true"
                   android:multiprocess="true" />
 
         <provider android:name="SmsProvider"
                   android:authorities="sms"
                   android:multiprocess="true"
+                  android:exported="true"
                   android:readPermission="android.permission.READ_SMS"
                   android:writePermission="android.permission.WRITE_SMS" />
 
         <provider android:name="MmsProvider"
                   android:authorities="mms"
                   android:multiprocess="true"
+                  android:exported="true"
                   android:readPermission="android.permission.READ_SMS"
                   android:writePermission="android.permission.WRITE_SMS">
             <grant-uri-permission android:pathPrefix="/part/" />
@@ -49,6 +52,7 @@
         <provider android:name="MmsSmsProvider"
                   android:authorities="mms-sms"
                   android:multiprocess="true"
+                  android:exported="true"
                   android:readPermission="android.permission.READ_SMS"
                   android:writePermission="android.permission.WRITE_SMS" />
     </application>