Dream settings refactor.

We will be re-using the grid UI for the dream complication picker, so
this change refactors some of that logic so it can be re-used in the
complication controller.

We also update some of the UI here to match the most recent UX
decisions.

http://screen/BxhAwZwQSVoxUmN.png

Test: locally on device
Test: make -j64 RunSettingsRoboTests ROBOTEST_FILTER="com.android.settings.dream.DreamPickerControllerTest"
Bug: 214250590
Bug: 215703483
Change-Id: I9fbfa0f0cd31ae3d119c7cd1a9562d4cdb203d6c

src/com/android/settings/dream/AutoFitGridLayoutManager.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.dream;
+
+import android.content.Context;
+
+import androidx.recyclerview.widget.GridLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.android.settings.R;
+
+/** Grid layout manager that calculates the number of columns for the screen size. */
+final class AutoFitGridLayoutManager extends GridLayoutManager {
+    private final float mColumnWidth;
+
+    AutoFitGridLayoutManager(Context context) {
+        super(context, /* spanCount= */ 1);
+        this.mColumnWidth = context
+                .getResources()
+                .getDimensionPixelSize(R.dimen.dream_item_min_column_width);
+    }
+
+    @Override
+    public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
+        final int totalSpace = getWidth() - getPaddingRight() - getPaddingLeft();
+        final int spanCount = Math.max(1, (int) (totalSpace / mColumnWidth));
+        setSpanCount(spanCount);
+        super.onLayoutChildren(recycler, state);
+    }
+}