Use String in CaptivePortalData underlying types

The venue friendly name comes from the network, and only plain strings
should be used in practice. writeCharSequence is also not usable in
CaptivePortalData, as it must build using module_api.

Use a String as the underlying type in CaptivePortalData, keeping
CharSequence in the API for consistency with UI-related elements.

This brings CaptivePortalData in line with downstream branches.

Bug: 183174863
Test: atest FrameworksNetTests
Merged-In: Ifa3ea9aae0cabf5757791c4ae13e6f551759ed97
Change-Id: Ic662d3b546d52f825f9c3a24c5e0d4ba03818ab0
diff --git a/framework/src/android/net/CaptivePortalData.java b/framework/src/android/net/CaptivePortalData.java
index 82dbd0f..53aa1b9 100644
--- a/framework/src/android/net/CaptivePortalData.java
+++ b/framework/src/android/net/CaptivePortalData.java
@@ -42,7 +42,7 @@
     private final long mByteLimit;
     private final long mExpiryTimeMillis;
     private final boolean mCaptive;
-    private final CharSequence mVenueFriendlyName;
+    private final String mVenueFriendlyName;
     private final int mVenueInfoUrlSource;
     private final int mUserPortalUrlSource;
 
@@ -73,14 +73,14 @@
         mByteLimit = byteLimit;
         mExpiryTimeMillis = expiryTimeMillis;
         mCaptive = captive;
-        mVenueFriendlyName = venueFriendlyName;
+        mVenueFriendlyName = venueFriendlyName == null ? null : venueFriendlyName.toString();
         mVenueInfoUrlSource = venueInfoUrlSource;
         mUserPortalUrlSource = userPortalUrlSource;
     }
 
     private CaptivePortalData(Parcel p) {
         this(p.readLong(), p.readParcelable(null), p.readParcelable(null), p.readBoolean(),
-                p.readLong(), p.readLong(), p.readBoolean(), p.readCharSequence(), p.readInt(),
+                p.readLong(), p.readLong(), p.readBoolean(), p.readString(), p.readInt(),
                 p.readInt());
     }
 
@@ -98,7 +98,7 @@
         dest.writeLong(mByteLimit);
         dest.writeLong(mExpiryTimeMillis);
         dest.writeBoolean(mCaptive);
-        dest.writeCharSequence(mVenueFriendlyName);
+        dest.writeString(mVenueFriendlyName);
         dest.writeInt(mVenueInfoUrlSource);
         dest.writeInt(mUserPortalUrlSource);
     }