Cleanup setGlobalProxy

This is a small cleanup of a function called by DevicePolicyManager
coming from a conflicting change. This no longer makes a concrete
difference but is still a good change.

Test: m services.devicepolicy
Bug: 172183305
Change-Id: I7ee907314ddb253eb4e97d177f0ea0ab3b58cf03
diff --git a/framework/src/android/net/ConnectivityManager.java b/framework/src/android/net/ConnectivityManager.java
index c6f4e0b..92ed7fc 100644
--- a/framework/src/android/net/ConnectivityManager.java
+++ b/framework/src/android/net/ConnectivityManager.java
@@ -3140,18 +3140,27 @@
     }
 
     /**
-     * Set a network-independent global http proxy.  This is not normally what you want
-     * for typical HTTP proxies - they are general network dependent.  However if you're
-     * doing something unusual like general internal filtering this may be useful.  On
-     * a private network where the proxy is not accessible, you may break HTTP using this.
+     * Set a network-independent global HTTP proxy.
      *
-     * @param p A {@link ProxyInfo} object defining the new global
-     *        HTTP proxy.  A {@code null} value will clear the global HTTP proxy.
+     * This sets an HTTP proxy that applies to all networks and overrides any network-specific
+     * proxy. If set, HTTP libraries that are proxy-aware will use this global proxy when
+     * accessing any network, regardless of what the settings for that network are.
+     *
+     * Note that HTTP proxies are by nature typically network-dependent, and setting a global
+     * proxy is likely to break networking on multiple networks. This method is only meant
+     * for device policy clients looking to do general internal filtering or similar use cases.
+     *
+     * {@see #getGlobalProxy}
+     * {@see LinkProperties#getHttpProxy}
+     *
+     * @param p A {@link ProxyInfo} object defining the new global HTTP proxy. Calling this
+     *          method with a {@code null} value will clear the global HTTP proxy.
      * @hide
      */
+    // Used by Device Policy Manager to set the global proxy.
     @SystemApi(client = MODULE_LIBRARIES)
     @RequiresPermission(android.Manifest.permission.NETWORK_STACK)
-    public void setGlobalProxy(@Nullable ProxyInfo p) {
+    public void setGlobalProxy(@Nullable final ProxyInfo p) {
         try {
             mService.setGlobalProxy(p);
         } catch (RemoteException e) {
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 70c9fe7..33aaca2 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -4962,7 +4962,7 @@
     }
 
     @Override
-    public void setGlobalProxy(final ProxyInfo proxyProperties) {
+    public void setGlobalProxy(@Nullable final ProxyInfo proxyProperties) {
         PermissionUtils.enforceNetworkStackPermission(mContext);
         mProxyTracker.setGlobalProxy(proxyProperties);
     }