Merge changes from topic "ns05" into sc-dev

* changes:
  [NS06] Implement the don't-reap mechanism
  [NS05] Feed network offer callbacks
diff --git a/framework/api/system-current.txt b/framework/api/system-current.txt
index 942a3de..95df8b8 100644
--- a/framework/api/system-current.txt
+++ b/framework/api/system-current.txt
@@ -314,9 +314,16 @@
     method public int getProviderId();
     method public void onNetworkRequestWithdrawn(@NonNull android.net.NetworkRequest);
     method public void onNetworkRequested(@NonNull android.net.NetworkRequest, @IntRange(from=0, to=99) int, int);
+    method @RequiresPermission(android.Manifest.permission.NETWORK_FACTORY) public void registerNetworkOffer(@NonNull android.net.NetworkScore, @NonNull android.net.NetworkCapabilities, @NonNull java.util.concurrent.Executor, @NonNull android.net.NetworkProvider.NetworkOfferCallback);
+    method @RequiresPermission(android.Manifest.permission.NETWORK_FACTORY) public void unregisterNetworkOffer(@NonNull android.net.NetworkProvider.NetworkOfferCallback);
     field public static final int ID_NONE = -1; // 0xffffffff
   }
 
+  public static interface NetworkProvider.NetworkOfferCallback {
+    method public void onNetworkNeeded(@NonNull android.net.NetworkRequest);
+    method public void onNetworkUnneeded(@NonNull android.net.NetworkRequest);
+  }
+
   public class NetworkReleasedException extends java.lang.Exception {
   }
 
@@ -331,14 +338,18 @@
 
   public final class NetworkScore implements android.os.Parcelable {
     method public int describeContents();
+    method public int getKeepConnectedReason();
     method public int getLegacyInt();
     method public void writeToParcel(@NonNull android.os.Parcel, int);
     field @NonNull public static final android.os.Parcelable.Creator<android.net.NetworkScore> CREATOR;
+    field public static final int KEEP_CONNECTED_FOR_HANDOVER = 1; // 0x1
+    field public static final int KEEP_CONNECTED_NONE = 0; // 0x0
   }
 
   public static final class NetworkScore.Builder {
     ctor public NetworkScore.Builder();
     method @NonNull public android.net.NetworkScore build();
+    method @NonNull public android.net.NetworkScore.Builder setKeepConnectedReason(int);
     method @NonNull public android.net.NetworkScore.Builder setLegacyInt(int);
   }
 
diff --git a/framework/src/android/net/ConnectivityManager.java b/framework/src/android/net/ConnectivityManager.java
index a9f8b8d..c9d37ad 100644
--- a/framework/src/android/net/ConnectivityManager.java
+++ b/framework/src/android/net/ConnectivityManager.java
@@ -3345,7 +3345,7 @@
      * @param score The prospective score of the network.
      * @param caps The prospective capabilities of the network.
      * @param callback The callback to call when this offer is needed or unneeded.
-     * @hide
+     * @hide exposed via the NetworkProvider class.
      */
     @RequiresPermission(anyOf = {
             NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
@@ -3368,7 +3368,7 @@
      *
      * @param callback The callback passed at registration time. This must be the same object
      *                 that was passed to {@link #offerNetwork}
-     * @hide
+     * @hide exposed via the NetworkProvider class.
      */
     public void unofferNetwork(@NonNull final INetworkOfferCallback callback) {
         try {
diff --git a/framework/src/android/net/INetworkOfferCallback.aidl b/framework/src/android/net/INetworkOfferCallback.aidl
index a6de173..ecfba21 100644
--- a/framework/src/android/net/INetworkOfferCallback.aidl
+++ b/framework/src/android/net/INetworkOfferCallback.aidl
@@ -51,10 +51,8 @@
     /**
      * Called when a network for this offer is needed to fulfill this request.
      * @param networkRequest the request to satisfy
-     * @param providerId the ID of the provider currently satisfying
-     *          this request, or NetworkProvider.ID_NONE if none.
      */
-    void onNetworkNeeded(in NetworkRequest networkRequest, int providerId);
+    void onNetworkNeeded(in NetworkRequest networkRequest);
 
     /**
      * Informs the registrant that the offer is no longer valuable to fulfill this request.
diff --git a/framework/src/android/net/NetworkProvider.java b/framework/src/android/net/NetworkProvider.java
index d859022..cfb7325 100644
--- a/framework/src/android/net/NetworkProvider.java
+++ b/framework/src/android/net/NetworkProvider.java
@@ -168,12 +168,16 @@
     }
 
     /** @hide */
-    // TODO : make @SystemApi when the impl is complete
+    @SystemApi
     public interface NetworkOfferCallback {
-        /** Called by the system when a network for this offer is needed to satisfy some
-         *  networking request. */
-        void onNetworkNeeded(@NonNull NetworkRequest request, int providerId);
-        /** Called by the system when this offer is no longer valuable for this request. */
+        /**
+         * Called by the system when a network for this offer is needed to satisfy some
+         * networking request.
+         */
+        void onNetworkNeeded(@NonNull NetworkRequest request);
+        /**
+         * Called by the system when this offer is no longer valuable for this request.
+         */
         void onNetworkUnneeded(@NonNull NetworkRequest request);
     }
 
@@ -188,9 +192,8 @@
         }
 
         @Override
-        public void onNetworkNeeded(final @NonNull NetworkRequest request,
-                final int providerId) {
-            mExecutor.execute(() -> callback.onNetworkNeeded(request, providerId));
+        public void onNetworkNeeded(final @NonNull NetworkRequest request) {
+            mExecutor.execute(() -> callback.onNetworkNeeded(request));
         }
 
         @Override
@@ -254,8 +257,11 @@
      *
      * The capabilities and score act as filters as to what requests the provider will see.
      * They are not promises, but for best performance, the providers should strive to put
-     * as much known information as possible in the offer. For capabilities in particular, it
-     * should put all NetworkAgent-managed capabilities a network may have, even if it doesn't
+     * as much known information as possible in the offer. For the score, it should put as
+     * strong a score as the networks will have, since this will filter what requests the
+     * provider sees – it's not a promise, it only serves to avoid sending requests that
+     * the provider can't ever hope to satisfy better than any current network. For capabilities,
+     * it should put all NetworkAgent-managed capabilities a network may have, even if it doesn't
      * have them at first. This applies to INTERNET, for example ; if a provider thinks the
      * network it can bring up for this offer may offer Internet access it should include the
      * INTERNET bit. It's fine if the brought up network ends up not actually having INTERNET.
@@ -268,9 +274,9 @@
      *
      * @hide
      */
-    // TODO : make @SystemApi when the impl is complete
+    @SystemApi
     @RequiresPermission(android.Manifest.permission.NETWORK_FACTORY)
-    public void offerNetwork(@NonNull final NetworkScore score,
+    public void registerNetworkOffer(@NonNull final NetworkScore score,
             @NonNull final NetworkCapabilities caps, @NonNull final Executor executor,
             @NonNull final NetworkOfferCallback callback) {
         // Can't offer a network with a provider that is not yet registered or already unregistered.
@@ -307,9 +313,9 @@
      *
      * @hide
      */
-    // TODO : make @SystemApi when the impl is complete
+    @SystemApi
     @RequiresPermission(android.Manifest.permission.NETWORK_FACTORY)
-    public void unofferNetwork(final @NonNull NetworkOfferCallback callback) {
+    public void unregisterNetworkOffer(final @NonNull NetworkOfferCallback callback) {
         final NetworkOfferCallbackProxy proxy = findProxyForCallback(callback);
         if (null == proxy) return;
         mProxies.remove(proxy);
diff --git a/framework/src/android/net/NetworkScore.java b/framework/src/android/net/NetworkScore.java
index 6584993..9786b09 100644
--- a/framework/src/android/net/NetworkScore.java
+++ b/framework/src/android/net/NetworkScore.java
@@ -16,6 +16,7 @@
 
 package android.net;
 
+import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.SystemApi;
 import android.os.Parcel;
@@ -23,6 +24,9 @@
 
 import com.android.internal.annotations.VisibleForTesting;
 
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
 /**
  * Object representing the quality of a network as perceived by the user.
  *
@@ -36,6 +40,17 @@
     // a migration.
     private final int mLegacyInt;
 
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(value = {
+            KEEP_CONNECTED_NONE,
+            KEEP_CONNECTED_FOR_HANDOVER
+    })
+    public @interface KeepConnectedReason { }
+
+    public static final int KEEP_CONNECTED_NONE = 0;
+    public static final int KEEP_CONNECTED_FOR_HANDOVER = 1;
+
     // Agent-managed policies
     // TODO : add them here, starting from 1
     /** @hide */
@@ -46,15 +61,20 @@
     // Bitmask of all the policies applied to this score.
     private final long mPolicies;
 
+    private final int mKeepConnectedReason;
+
     /** @hide */
-    NetworkScore(final int legacyInt, final long policies) {
+    NetworkScore(final int legacyInt, final long policies,
+            @KeepConnectedReason final int keepConnectedReason) {
         mLegacyInt = legacyInt;
         mPolicies = policies;
+        mKeepConnectedReason = keepConnectedReason;
     }
 
     private NetworkScore(@NonNull final Parcel in) {
         mLegacyInt = in.readInt();
         mPolicies = in.readLong();
+        mKeepConnectedReason = in.readInt();
     }
 
     public int getLegacyInt() {
@@ -62,6 +82,13 @@
     }
 
     /**
+     * Returns the keep-connected reason, or KEEP_CONNECTED_NONE.
+     */
+    public int getKeepConnectedReason() {
+        return mKeepConnectedReason;
+    }
+
+    /**
      * @return whether this score has a particular policy.
      *
      * @hide
@@ -80,6 +107,7 @@
     public void writeToParcel(@NonNull final Parcel dest, final int flags) {
         dest.writeInt(mLegacyInt);
         dest.writeLong(mPolicies);
+        dest.writeInt(mKeepConnectedReason);
     }
 
     @Override
@@ -108,6 +136,7 @@
         private static final long POLICY_NONE = 0L;
         private static final int INVALID_LEGACY_INT = Integer.MIN_VALUE;
         private int mLegacyInt = INVALID_LEGACY_INT;
+        private int mKeepConnectedReason = KEEP_CONNECTED_NONE;
 
         /**
          * Sets the legacy int for this score.
@@ -124,12 +153,23 @@
         }
 
         /**
+         * Set the keep-connected reason.
+         *
+         * This can be reset by calling it again with {@link KEEP_CONNECTED_NONE}.
+         */
+        @NonNull
+        public Builder setKeepConnectedReason(@KeepConnectedReason final int reason) {
+            mKeepConnectedReason = reason;
+            return this;
+        }
+
+        /**
          * Builds this NetworkScore.
          * @return The built NetworkScore object.
          */
         @NonNull
         public NetworkScore build() {
-            return new NetworkScore(mLegacyInt, POLICY_NONE);
+            return new NetworkScore(mLegacyInt, POLICY_NONE, mKeepConnectedReason);
         }
     }
 }