Made following changes to Settings:

- Moved the Voice Input setting from Digital assistant app to Languages & input.
- Bundled Voice Input and Text-to-speech settings together under Speech
  category.

Bug: 218609449

Test: refactoring CL. Existing unit tests still pass.
Change-Id: I3107a410ed35685f5f1081cbe448b105b5c79c24

src/com/android/settings/language/DefaultVoiceInputPicker.java

@@ -0,0 +1,123 @@
+/*
+ * 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.language;
+
+import android.app.settings.SettingsEnums;
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.provider.Settings;
+import android.text.TextUtils;
+
+import com.android.settings.R;
+import com.android.settings.applications.defaultapps.DefaultAppPickerFragment;
+import com.android.settingslib.applications.DefaultAppInfo;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/** Controls the Voice Input setting. */
+public class DefaultVoiceInputPicker extends DefaultAppPickerFragment {
+
+    private VoiceInputHelper mHelper;
+
+    @Override
+    public int getMetricsCategory() {
+        return SettingsEnums.DEFAULT_VOICE_INPUT_PICKER;
+    }
+
+    @Override
+    public void onAttach(Context context) {
+        super.onAttach(context);
+        mHelper = new VoiceInputHelper(context);
+        mHelper.buildUi();
+    }
+
+    @Override
+    protected int getPreferenceScreenResId() {
+        return R.xml.default_voice_settings;
+    }
+
+    @Override
+    protected List<VoiceInputDefaultAppInfo> getCandidates() {
+        final List<VoiceInputDefaultAppInfo> candidates = new ArrayList<>();
+        final Context context = getContext();
+
+        for (VoiceInputHelper.RecognizerInfo info : mHelper.mAvailableRecognizerInfos) {
+            final boolean enabled = true;
+            candidates.add(new VoiceInputDefaultAppInfo(context, mPm, mUserId, info, enabled));
+        }
+        return candidates;
+    }
+
+    @Override
+    protected String getDefaultKey() {
+        final ComponentName currentService = getCurrentService(mHelper);
+        if (currentService == null) {
+            return null;
+        }
+        return currentService.flattenToShortString();
+    }
+
+    @Override
+    protected boolean setDefaultKey(String value) {
+        for (VoiceInputHelper.RecognizerInfo info : mHelper.mAvailableRecognizerInfos) {
+            if (TextUtils.equals(value, info.mKey)) {
+                Settings.Secure.putString(getContext().getContentResolver(),
+                        Settings.Secure.VOICE_RECOGNITION_SERVICE, value);
+                return true;
+            }
+        }
+        return true;
+    }
+
+    /** Gets the current recognition service component. */
+    public static ComponentName getCurrentService(VoiceInputHelper helper) {
+        return helper.mCurrentRecognizer;
+    }
+
+    /** Stores the info of the Voice Input provider. */
+    public static class VoiceInputDefaultAppInfo extends DefaultAppInfo {
+
+        public VoiceInputHelper.BaseInfo mInfo;
+
+        public VoiceInputDefaultAppInfo(Context context, PackageManager pm, int userId,
+                VoiceInputHelper.BaseInfo info, boolean enabled) {
+            super(context, pm, userId, info.mComponentName, null /* summary */, enabled);
+            mInfo = info;
+        }
+
+        @Override
+        public String getKey() {
+            return mInfo.mKey;
+        }
+
+        @Override
+        public CharSequence loadLabel() {
+            return mInfo.mLabel;
+        }
+
+        /** Gets the setting intent. */
+        public Intent getSettingIntent() {
+            if (mInfo.mSettings == null) {
+                return null;
+            }
+            return new Intent(Intent.ACTION_MAIN).setComponent(mInfo.mSettings);
+        }
+    }
+}