android: Add UI setting for experimental features (#40054)

These commits add a new settings screen to the app, then add:
1) a setting to disable a developer-targeted UI element (an indicator
about whether the app is polling continuously for events)
2) a toggle for experimental web platform features

The page needs to be reloaded after switching the toggle before any
changes can be observed.

Testing: Manually tested by visiting https://developer.mozilla.org with
the setting enabled and disabled. No automated testing for Android yet.
Fixes: #39791

---------

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

support/android/apk/servoapp/build.gradle.kts

@@ -172,4 +172,5 @@ dependencies {
     implementation("androidx.appcompat:appcompat:1.6.1")
     implementation("com.google.android.material:material:1.9.0")
     implementation("androidx.constraintlayout:constraintlayout:2.1.3")
+    implementation("androidx.preference:preference-ktx:1.2.0")
 }

support/android/apk/servoapp/src/main/AndroidManifest.xml

@@ -43,6 +43,11 @@
               <data android:mimeType="application/xhtml+xml"/>
             </intent-filter>
         </activity>
+        <activity android:name=".SettingsActivity"
+            android:configChanges="density|keyboardHidden|navigation|orientation|screenSize|uiMode"
+            android:exported="true"
+            android:theme="@style/AppTheme">
+        </activity>
     </application>
 
 </manifest>

support/android/apk/servoapp/src/main/java/org/servo/servoshell/MainActivity.java

@@ -9,8 +9,10 @@ import android.app.Activity;
 import android.app.AlertDialog;
 import android.content.Context;
 import android.content.Intent;
+import android.content.SharedPreferences;
 import android.net.Uri;
 import android.os.Bundle;
+import android.preference.PreferenceManager;
 import android.system.ErrnoException;
 import android.system.Os;
 import android.util.Log;
@@ -45,6 +47,17 @@ public class MainActivity extends Activity implements Servo.Client {
     boolean mCanGoBack;
     MediaSession mMediaSession;
 
+    class Settings {
+        Settings(SharedPreferences preferences) {
+            showAnimatingIndicator = preferences.getBoolean("animating_indicator", false);
+            experimental = preferences.getBoolean("experimental", false);
+        }
+
+        boolean showAnimatingIndicator;
+        boolean experimental;
+    }
+    Settings mSettings;
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -61,6 +74,8 @@ public class MainActivity extends Activity implements Servo.Client {
         mIdleText = findViewById(R.id.redrawing);
         mCanGoBack = false;
 
+        updateSettingsIfNecessary(true);
+
         mBackButton.setEnabled(false);
         mFwdButton.setEnabled(false);
 
@@ -82,7 +97,7 @@ public class MainActivity extends Activity implements Servo.Client {
         Intent intent = getIntent();
         String args = intent.getStringExtra("servoargs");
         String log = intent.getStringExtra("servolog");
-        mServoView.setServoArgs(args, log);
+        mServoView.setServoArgs(args, log, mSettings.experimental);
 
         if (Intent.ACTION_VIEW.equals(intent.getAction())) {
             mServoView.loadUri(intent.getData().toString());
@@ -126,6 +141,11 @@ public class MainActivity extends Activity implements Servo.Client {
     }
 
     // From activity_main.xml:
+    public void onSettingsClicked(View v) {
+        Intent myIntent = new Intent(this, SettingsActivity.class);
+        startActivity(myIntent);
+    }
+
     public void onReloadClicked(View v) {
         mServoView.reload();
     }
@@ -243,6 +263,7 @@ public class MainActivity extends Activity implements Servo.Client {
     public void onResume() {
         mServoView.onResume();
         super.onResume();
+        updateSettingsIfNecessary(false);
     }
 
     @Override
@@ -291,4 +312,31 @@ public class MainActivity extends Activity implements Servo.Client {
 
         mMediaSession.setPositionState(duration, position, playbackRate);
     }
+
+    public void onAnimatingIndicatorPrefChanged(boolean value) {
+        if (value) {
+            mIdleText.setVisibility(View.VISIBLE);
+        } else {
+            mIdleText.setVisibility(View.GONE);
+        }
+    }
+
+    public void onExperimentalPrefChanged(boolean value) {
+        mServoView.setExperimentalMode(value);
+    }
+
+    public void updateSettingsIfNecessary(boolean force) {
+        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
+        Settings updated = new Settings(preferences);
+
+        if (force || updated.showAnimatingIndicator != mSettings.showAnimatingIndicator) {
+            onAnimatingIndicatorPrefChanged(updated.showAnimatingIndicator);
+        }
+
+        if (force || updated.experimental != mSettings.experimental) {
+            onExperimentalPrefChanged(updated.experimental);
+        }
+
+        mSettings = updated;
+    }
 }

support/android/apk/servoapp/src/main/java/org/servo/servoshell/SettingsActivity.java

@@ -0,0 +1,22 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+package org.servo.servoshell;
+
+import android.os.Bundle;
+import androidx.appcompat.app.AppCompatActivity;
+
+public class SettingsActivity extends AppCompatActivity {
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_settings);
+
+        getSupportFragmentManager()
+            .beginTransaction()
+            .replace(R.id.settings_container, new SettingsFragment())
+            .commit();
+     }
+}

support/android/apk/servoapp/src/main/java/org/servo/servoshell/SettingsFragment.java

@@ -0,0 +1,14 @@
+package org.servo.servoshell;
+
+import android.os.Bundle;
+import androidx.preference.PreferenceFragmentCompat;
+import androidx.preference.SwitchPreferenceCompat;
+
+public class SettingsFragment extends PreferenceFragmentCompat {
+    @Override
+    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
+        setPreferencesFromResource(R.xml.preferences, rootKey);
+
+       SwitchPreferenceCompat animatingPref = findPreference("animating_indicator");
+    }
+}

support/android/apk/servoapp/src/main/res/layout/activity_main.xml

@@ -126,7 +126,19 @@
                 android:onClick="onForwardClicked"
                 android:src="@drawable/history_forward" />
 
+            <ImageButton
+                android:id="@+id/settingsbutton"
+                style="@android:style/Widget.Material.ImageButton"
+                android:layout_width="wrap_content"
+                android:layout_height="match_parent"
+                android:layout_weight="1"
+                android:scaleType="centerInside"
+                android:adjustViewBounds="true"
+                android:onClick="onSettingsClicked"
+                android:src="@drawable/kebab" />
+
         </LinearLayout>
 
     </LinearLayout>
+
 </androidx.constraintlayout.widget.ConstraintLayout>

support/android/apk/servoapp/src/main/res/layout/activity_settings.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context="org.servo.servoshell.SettingsActivity">
+
+    <androidx.fragment.app.FragmentContainerView
+        xmlns:android="http://schemas.android.com/apk/res/android"
+        android:id="@+id/settings_container"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:name="org.servo.servoshell.SettingsFragment" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>

support/android/apk/servoapp/src/main/res/xml/preferences.xml

@@ -0,0 +1,15 @@
+<PreferenceScreen
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <SwitchPreferenceCompat
+        android:key="experimental"
+        android:defaultValue="false"
+        android:title="Enable experimental web platform features"/>
+
+    <SwitchPreferenceCompat
+        android:key="animating_indicator"
+        android:defaultValue="false"
+        android:title="Enable idle/animating indicator"/>
+
+</PreferenceScreen>

support/android/apk/servoview/src/main/java/org/servo/servoview/JNIServo.java

@@ -67,6 +67,8 @@ public class JNIServo {
 
     public native void mediaSessionAction(int action);
 
+    public native void setExperimentalMode(boolean enable);
+
     public static class ServoOptions {
       public String args;
       public String url;
@@ -77,6 +79,7 @@ public class JNIServo {
       public String logStr;
       public String gstDebugStr;
       public boolean enableLogs = false;
+      public boolean experimentalMode = false;
     }
 
     public static class ServoCoordinates {

support/android/apk/servoview/src/main/java/org/servo/servoview/Servo.java

@@ -167,6 +167,10 @@ public class Servo {
         mRunCallback.inGLThread(() -> mJNI.mediaSessionAction(action));
     }
 
+    public void setExperimentalMode(boolean enable) {
+        mRunCallback.inGLThread(() -> mJNI.setExperimentalMode(enable));
+    }
+
     public interface Client {
         void onAlert(String message);
 

support/android/apk/servoview/src/main/java/org/servo/servoview/ServoView.java

@@ -59,6 +59,7 @@ public class ServoView extends SurfaceView
     private ScaleGestureDetector mScaleGestureDetector;
     private OverScroller mScroller;
 
+    private boolean mExperimentalMode;
     private boolean mZooming;
     private float mZoomFactor = 1;
     private boolean mRedrawing;
@@ -95,9 +96,10 @@ public class ServoView extends SurfaceView
         mClient = client;
     }
 
-    public void setServoArgs(String args, String log) {
+    public void setServoArgs(String args, String log, boolean experimentalMode) {
         mServoArgs = args;
         mServoLog = log;
+        mExperimentalMode = experimentalMode;
     }
 
     // RunCallback
@@ -362,6 +364,12 @@ public class ServoView extends SurfaceView
         mServo.mediaSessionAction(action);
     }
 
+    public void setExperimentalMode(boolean enable) {
+        if (mServo != null) {
+            mServo.setExperimentalMode(enable);
+        }
+    }
+
     class GLThread extends Thread implements SurfaceHolder.Callback {
         private Activity mActivity;
         private ServoView mServoView;
@@ -384,6 +392,7 @@ public class ServoView extends SurfaceView
             options.coordinates = coords;
             options.enableLogs = true;
             options.enableSubpixelTextAntialiasing = true;
+            options.experimentalMode = mServoView.mExperimentalMode;
 
             DisplayMetrics metrics = new DisplayMetrics();
             mActivity.getWindowManager().getDefaultDisplay().getMetrics(metrics);