Tie ContextualWifiSlice to UI instead of garbage collector

- Introduce a static long in SliceFeatureProvider that updates once
  every "session". A session is when user is in an UI (screen rotation,
  going to subpage, etc does not break the continuation of session).

- Use session token in ContextualWifiSlice to determine when to refresh,
  instead of relying on WeakHashMap from CustomSliceManager.
  WeakHashMap can be cleaned up at any time by gc so it doesn't match
  what we want on the UI.

- Also as a side fix, merged CustomSliceManager into
  SliceFeatureProvider.

Fixes: 123937830
Test: robo
Change-Id: I199bceceb208b99a32f3f08e624787b5a03e73a9

src/com/android/settings/slices/SlicesFeatureProviderImpl.java

@@ -17,19 +17,23 @@
 package com.android.settings.slices;
 
 import android.content.Context;
+import android.net.Uri;
+import android.os.SystemClock;
 
 import com.android.settings.network.telephony.Enhanced4gLteSliceHelper;
 import com.android.settings.wifi.calling.WifiCallingSliceHelper;
 import com.android.settingslib.utils.ThreadUtils;
 
+import java.util.Random;
+
 /**
  * Manages Slices in Settings.
  */
 public class SlicesFeatureProviderImpl implements SlicesFeatureProvider {
 
+    private long mUiSessionToken;
     private SlicesIndexer mSlicesIndexer;
     private SliceDataConverter mSliceDataConverter;
-    private CustomSliceManager mCustomSliceManager;
 
     @Override
     public SliceDataConverter getSliceDataConverter(Context context) {
@@ -40,11 +44,13 @@ public class SlicesFeatureProviderImpl implements SlicesFeatureProvider {
     }
 
     @Override
-    public CustomSliceManager getCustomSliceManager(Context context) {
-        if (mCustomSliceManager == null) {
-            mCustomSliceManager = new CustomSliceManager(context.getApplicationContext());
-        }
-        return mCustomSliceManager;
+    public void newUiSession() {
+        mUiSessionToken = SystemClock.elapsedRealtime();
+    }
+
+    @Override
+    public long getUiSessionToken() {
+        return mUiSessionToken;
     }
 
     @Override
@@ -69,6 +75,18 @@ public class SlicesFeatureProviderImpl implements SlicesFeatureProvider {
         return new Enhanced4gLteSliceHelper(context);
     }
 
+    @Override
+    public CustomSliceable getSliceableFromUri(Context context, Uri uri) {
+        final Uri newUri = CustomSliceRegistry.removeParameterFromUri(uri);
+        final Class clazz = CustomSliceRegistry.getSliceClassByUri(newUri);
+        if (clazz == null) {
+            throw new IllegalArgumentException("No Slice found for uri: " + uri);
+        }
+
+        final CustomSliceable sliceable = CustomSliceable.createInstance(context, clazz);
+        return sliceable;
+    }
+
     private SlicesIndexer getSliceIndexer(Context context) {
         if (mSlicesIndexer == null) {
             mSlicesIndexer = new SlicesIndexer(context.getApplicationContext());