Permissions to protect bandwidth statistics.

Introduces new "net_bw_stats" group which will protect reading
detailed bandwidth statistics from the kernel.  Also introduce
"net_bw_acct" group which will enable specific applications to
request that their network traffic be counted against other UIDs.

This change associates manifest permissions with the low-level GIDs.

Change-Id: If3fc28053afda201ff305d798a8878ff1f35b997
diff --git a/core/res/AndroidManifest.xml b/core/res/AndroidManifest.xml
index 47902a8..53e063a 100644
--- a/core/res/AndroidManifest.xml
+++ b/core/res/AndroidManifest.xml
@@ -1393,6 +1393,14 @@
         android:description="@string/permdesc_manageNetworkPolicy"
         android:protectionLevel="signature" />
 
+    <!-- Allows an application to account its network traffic against other UIDs. Used
+         by system services like download manager and media server. Not for use by
+         third party apps. @hide -->
+    <permission android:name="android.permission.MODIFY_NETWORK_ACCOUNTING"
+        android:label="@string/permlab_modifyNetworkAccounting"
+        android:description="@string/permdesc_modifyNetworkAccounting"
+        android:protectionLevel="signatureOrSystem" />
+
     <!-- C2DM permission. 
          @hide Used internally.
      -->