Fix a bug where the PAC proxy port is not set correctly.

Test: new test for this behavior in the preliminary change
Test: FrameworksNetTests NetworkStackTests
Fixes: 138810051
Fixes: 140610528
Change-Id: I95a979d232fb60ece2e33e972bf5d66d20357a1f

framework/src/android/net/ProxyInfo.java

@@ -47,6 +47,8 @@ public class ProxyInfo implements Parcelable {
     private final int mPort;
     private final String mExclusionList;
     private final String[] mParsedExclusionList;
+    // Uri.EMPTY if none.
+    @NonNull
     private final Uri mPacFileUrl;
 
     /**
@@ -256,6 +258,14 @@ public class ProxyInfo implements Parcelable {
         return proxy;
     }
 
+    /**
+     * @hide
+     * @return whether this proxy uses a Proxy Auto Configuration URL.
+     */
+    public boolean isPacProxy() {
+        return !Uri.EMPTY.equals(mPacFileUrl);
+    }
+
     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder();