Add configuration flag for disabling visual voicemail.

Some devices do not support visual voicemail and must still show
notifications despite what value is set here.

Change-Id: Ie4b68cd8c9f4d90e06be4f0c1a4c687106034a80
diff --git a/res/values/config.xml b/res/values/config.xml
index 2c9aa3a..826cd74 100755
--- a/res/values/config.xml
+++ b/res/values/config.xml
@@ -193,4 +193,6 @@
     <string name="config_simUnlockUiPackage" translatable="false">@null</string>
     <!-- Class name for the SIM unlock dialog.[DO NOT TRANSLATE] -->
     <string name="config_simUnlockUiClass" translatable="false">@null</string>
+
+    <bool name="allow_visual_voicemail">true</bool>
 </resources>
diff --git a/src/com/android/phone/vvm/omtp/SimChangeReceiver.java b/src/com/android/phone/vvm/omtp/SimChangeReceiver.java
index 9aff2d7..e467bb3 100644
--- a/src/com/android/phone/vvm/omtp/SimChangeReceiver.java
+++ b/src/com/android/phone/vvm/omtp/SimChangeReceiver.java
@@ -28,6 +28,7 @@
 import com.android.internal.telephony.PhoneConstants;
 import com.android.internal.telephony.TelephonyIntents;
 import com.android.phone.PhoneUtils;
+import com.android.phone.R;
 import com.android.phone.settings.VisualVoicemailSettingsUtil;
 import com.android.phone.vvm.omtp.sync.OmtpVvmSourceManager;
 
@@ -78,8 +79,10 @@
                     boolean isEnabledInSettings =
                             VisualVoicemailSettingsUtil.isVisualVoicemailEnabled(context,
                             phoneAccount);
-                    boolean isEnabled = isUserSet ? isEnabledInSettings :
-                        carrierConfigHelper.isEnabledByDefault();
+                    boolean isSupported =
+                            context.getResources().getBoolean(R.bool.allow_visual_voicemail);
+                    boolean isEnabled = isSupported && (isUserSet ? isEnabledInSettings :
+                        carrierConfigHelper.isEnabledByDefault());
 
                     if (!isUserSet) {
                         // Preserve the previous setting for "isVisualVoicemailEnabled" if it is