如何从Bubblewrap生成的TWA中获取CustomTabsSession对象

我用Bubblewrap创建了一个TWA，应用运行正常。现在需要发送WebMessage，根据官方文档，这可以通过CustomTabs实现，但我不知道如何从现有类中获取活跃的CustomTabsSession对象来进行操作。

AndroidManifest.xml #

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.myapplication.twa">

    <application
        android:name="Application"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/appName"
        android:manageSpaceActivity="com.google.androidbrowserhelper.trusted.ManageDataLauncherActivity"
        android:supportsRtl="true"
        android:theme="@android:style/Theme.Translucent.NoTitleBar">

        <meta-data
            android:name="asset_statements"
            android:resource="@string/assetStatements" />

        <meta-data
            android:name="web_manifest_url"
            android:value="@string/webManifestUrl" />

        <meta-data
            android:name="twa_generator"
            android:value="@string/generatorApp" />
            
        <activity android:name="com.google.androidbrowserhelper.trusted.ManageDataLauncherActivity">
            <meta-data
                android:name="android.support.customtabs.trusted.MANAGE_SPACE_URL"
                android:value="@string/launchUrl" />
        </activity>

        <activity android:name="LauncherActivity"
            android:alwaysRetainTaskState="true"
            android:label="@string/launcherName"
            android:exported="true">
            <meta-data android:name="android.support.customtabs.trusted.DEFAULT_URL"
                android:value="@string/launchUrl" />

            <meta-data
                android:name="android.support.customtabs.trusted.STATUS_BAR_COLOR"
                android:resource="@color/colorPrimary" />

            <meta-data
                android:name="android.support.customtabs.trusted.NAVIGATION_BAR_COLOR"
                android:resource="@color/navigationColor" />

            <meta-data
                android:name="android.support.customtabs.trusted.NAVIGATION_BAR_COLOR_DARK"
                android:resource="@color/navigationColorDark" />

            <meta-data
                android:name="androix.browser.trusted.NAVIGATION_BAR_DIVIDER_COLOR"
                android:resource="@color/navigationDividerColor" />

            <meta-data
                android:name="androix.browser.trusted.NAVIGATION_BAR_DIVIDER_COLOR_DARK"
                android:resource="@color/navigationDividerColorDark" />

            <meta-data android:name="android.support.customtabs.trusted.SPLASH_IMAGE_DRAWABLE"
                android:resource="@drawable/splash"/>

            <meta-data android:name="android.support.customtabs.trusted.SPLASH_SCREEN_BACKGROUND_COLOR"
                android:resource="@color/backgroundColor"/>

            <meta-data android:name="android.support.customtabs.trusted.SPLASH_SCREEN_FADE_OUT_DURATION"
                android:value="@integer/splashScreenFadeOutDuration"/>

            <meta-data android:name="android.support.customtabs.trusted.FILE_PROVIDER_AUTHORITY"
                android:value="@string/providerAuthority"/>

            <meta-data android:name="android.app.shortcuts" android:resource="@xml/shortcuts" />

            <meta-data android:name="android.support.customtabs.trusted.FALLBACK_STRATEGY"
                android:value="@string/fallbackType" />

            <meta-data android:name="android.support.customtabs.trusted.DISPLAY_MODE"
                android:value="immersive" />

            <meta-data android:name="android.support.customtabs.trusted.SCREEN_ORIENTATION"
                android:value="@string/orientation"/>

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

            <intent-filter android:autoVerify="true">
                <action android:name="android.intent.action.VIEW"/>
                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.BROWSABLE"/>
                <data android:scheme="https"
                    android:host="@string/hostName"/>
            </intent-filter>

        </activity>

        <activity android:name="com.google.androidbrowserhelper.trusted.FocusActivity" />

        <activity android:name="com.google.androidbrowserhelper.trusted.WebViewFallbackActivity"
            android:configChanges="orientation|screenSize" />

        <provider
            android:name="androidx.core.content.FileProvider"
            android:authorities="@string/providerAuthority"
            android:grantUriPermissions="true"
            android:exported="false">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/filepaths" />
        </provider>

        <service
            android:name=".DelegationService"
            android:enabled="@bool/enableNotification"
            android:exported="@bool/enableNotification">

            <meta-data
                android:name="android.support.customtabs.trusted.SMALL_ICON"
                android:resource="@drawable/ic_notification_icon" />

            <intent-filter>
                <action android:name="android.support.customtabs.trusted.TRUSTED_WEB_ACTIVITY_SERVICE"/>
                <category android:name="android.intent.category.DEFAULT"/>
            </intent-filter>
        </service>

        <activity android:name=
        "com.google.androidbrowserhelper.locationdelegation.PermissionRequestActivity"/>

    </application>
</manifest>

LauncherActivity.java #

import android.content.pm.ActivityInfo;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;

public class LauncherActivity
        extends com.google.androidbrowserhelper.trusted.LauncherActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.O) {
            setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED);
        } else {
            setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED);
        }
    }

    @Override
    protected Uri getLaunchingUrl() {
        // 获取原始启动URL
        Uri uri = super.getLaunchingUrl();

        return uri;
    }
}

Application.java #

public class Application extends android.app.Application {

  @Override
  public void onCreate() {
      super.onCreate();
  }
}

内容的提问来源于stack exchange，提问作者Actticus