Secure DNS UI for Android

This replicates the desktop UI, with platform-appropriate adjustments.

Bug: 1040146
Change-Id: I33cea7dd37086d87580e149404ed3619a828ee45
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2240456Reviewed-by: Peter Conn <peconn@chromium.org>
Reviewed-by: Natalie Chouinard <chouinard@chromium.org>
Commit-Queue: Ben Schwartz <bemasc@chromium.org>
Auto-Submit: Ben Schwartz <bemasc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#782049}

chrome/android/chrome_java_resources.gni

@@ -1002,6 +1002,8 @@ chrome_java_resources = [
   "java/res/layout/search_engine.xml",
   "java/res/layout/search_engine_recent_title.xml",
   "java/res/layout/search_widget_template.xml",
+  "java/res/layout/secure_dns_provider_preference.xml",
+  "java/res/layout/secure_dns_provider_spinner_item.xml",
   "java/res/layout/send_tab_to_self_device_picker_item.xml",
   "java/res/layout/send_tab_to_self_device_picker_list.xml",
   "java/res/layout/send_tab_to_self_device_picker_toolbar.xml",
@@ -1119,6 +1121,7 @@ chrome_java_resources = [
   "java/res/xml/notifications_preferences.xml",
   "java/res/xml/privacy_preferences.xml",
   "java/res/xml/search_widget_info.xml",
+  "java/res/xml/secure_dns_settings.xml",
   "java/res/xml/sync_and_services_preferences.xml",
   "java/res/xml/theme_preferences.xml",
   "java/res/xml/tracing_preferences.xml",

chrome/android/chrome_java_sources.gni

@@ -1336,6 +1336,8 @@ chrome_java_sources = [
   "java/src/org/chromium/chrome/browser/privacy/settings/DoNotTrackSettings.java",
   "java/src/org/chromium/chrome/browser/privacy/settings/PrivacyPreferencesManager.java",
   "java/src/org/chromium/chrome/browser/privacy/settings/PrivacySettings.java",
+  "java/src/org/chromium/chrome/browser/privacy/settings/SecureDnsProviderPreference.java",
+  "java/src/org/chromium/chrome/browser/privacy/settings/SecureDnsSettings.java",
   "java/src/org/chromium/chrome/browser/provider/BaseColumns.java",
   "java/src/org/chromium/chrome/browser/provider/BookmarkColumns.java",
   "java/src/org/chromium/chrome/browser/provider/ChromeBrowserProvider.java",

chrome/android/java/res/layout/secure_dns_provider_preference.xml

+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2020 The Chromium Authors. All rights reserved.
+     Use of this source code is governed by a BSD-style license that can be
+     found in the LICENSE file. -->
+
+<LinearLayout 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="wrap_content"
+    android:background="?android:attr/selectableItemBackground"
+    android:gravity="center_vertical"
+    android:orientation="vertical"
+    android:paddingBottom="8dp"
+    android:focusable="false">
+
+    <org.chromium.components.browser_ui.widget.RadioButtonWithDescriptionLayout
+        android:id="@+id/mode_group"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent">
+
+      <org.chromium.components.browser_ui.widget.RadioButtonWithDescription
+          android:id="@+id/automatic"
+          android:layout_width="match_parent"
+          android:layout_height="wrap_content"
+          android:minHeight="@dimen/min_touch_target_size"
+          android:background="?attr/selectableItemBackground"
+          app:primaryText="@string/settings_automatic_mode_label"
+          app:descriptionText="@string/settings_automatic_mode_description"/>
+
+      <org.chromium.components.browser_ui.widget.RadioButtonWithDescription
+          android:id="@+id/secure"
+          android:layout_width="match_parent"
+          android:layout_height="wrap_content"
+          android:minHeight="@dimen/min_touch_target_size"
+          android:background="?attr/selectableItemBackground"
+          app:primaryText="@string/settings_secure_dropdown_mode_description"/>
+
+    </org.chromium.components.browser_ui.widget.RadioButtonWithDescriptionLayout>
+
+    <!-- This container is relocated into @id/secure as an accessory view. -->
+    <LinearLayout
+        android:id="@+id/selection_container"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:background="?android:attr/selectableItemBackground"
+        android:paddingStart="@dimen/radio_button_accessory_view_padding_start"
+        android:paddingEnd="@dimen/radio_button_accessory_view_padding_end"
+        android:gravity="start"
+        android:orientation="vertical"
+        android:focusable="false">
+        <Spinner
+            android:id="@+id/dropdown_spinner"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:paddingStart="4dp"/>
+        <TextView
+            android:id="@+id/privacy_policy"
+            android:paddingStart="4dp"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:textAppearance="@style/TextAppearance.TextMedium.Secondary"
+            android:text="@string/settings_secure_dropdown_mode_privacy_policy"/>
+        <com.google.android.material.textfield.TextInputLayout
+            android:id="@+id/custom_server_layout"
+            android:labelFor="@id/custom_server"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content">
+
+            <EditText
+                tools:ignore="LabelFor"
+                android:id="@+id/custom_server"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:singleLine="true"
+                android:textAppearance="@style/TextAppearance.TextLarge.Primary"
+                android:inputType="textUri"
+                android:imeOptions="actionDone"
+                android:hint="@string/settings_secure_dns_custom_placeholder"/>
+
+        </com.google.android.material.textfield.TextInputLayout>
+
+    </LinearLayout>
+</LinearLayout>

chrome/android/java/res/layout/secure_dns_provider_spinner_item.xml

+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2020 The Chromium Authors. All rights reserved.
+     Use of this source code is governed by a BSD-style license that can be
+     found in the LICENSE file. -->
+
+<!-- Copy of @layout/preference_spinner_single_line_item with padding removed. -->
+<TextView xmlns:android="http://schemas.android.com/apk/res/android"
+    style="?android:attr/spinnerItemStyle"
+    android:maxLines="1"
+    android:textAppearance="@style/TextAppearance.TextLarge.Primary"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:ellipsize="marquee"
+    android:textAlignment="inherit"
+    android:paddingStart="0dp"/>

chrome/android/java/res/xml/privacy_preferences.xml

@@ -23,6 +23,10 @@
         android:fragment="org.chromium.chrome.browser.privacy.settings.DoNotTrackSettings"
         android:key="do_not_track"
         android:title="@string/do_not_track_title" />
+    <org.chromium.components.browser_ui.settings.ChromeBasePreference
+        android:key="secure_dns"
+        android:title="@string/settings_secure_dns_title"
+        android:fragment="org.chromium.chrome.browser.privacy.settings.SecureDnsSettings" />
     <Preference
         android:key="clear_browsing_data"
         android:title="@string/clear_browsing_data_title"

chrome/android/java/res/xml/secure_dns_settings.xml

+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2020 The Chromium Authors. All rights reserved.
+     Use of this source code is governed by a BSD-style license that can be
+     found in the LICENSE file. -->
+
+<PreferenceScreen
+    xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <org.chromium.components.browser_ui.settings.ChromeSwitchPreference
+        android:key="secure_dns_switch"
+        android:persistent="false"
+        android:title="@string/settings_secure_dns_title"
+        android:summary="@string/settings_secure_dns_description" />
+
+    <org.chromium.chrome.browser.privacy.settings.SecureDnsProviderPreference
+        android:key="secure_dns_provider" />
+
+</PreferenceScreen>

chrome/android/java/src/org/chromium/chrome/browser/privacy/settings/PrivacyPreferencesManager.java

@@ -9,6 +9,7 @@ import android.content.Context;
 import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.VisibleForTesting;
 
 import org.chromium.base.CommandLine;
@@ -41,19 +42,19 @@ public class PrivacyPreferencesManager implements CrashReportingPermissionManage
      * for display in the UI.
      */
     static class DohEntry {
-        final String mName; // Display name
-        final String mTemplate; // URI template, or "" for the custom entry.
-        final String mPrivacy; // Privacy policy link
+        public final @NonNull String name; // Display name
+        public final @NonNull String template; // URI template, or "" for the custom entry.
+        public final @NonNull String privacy; // Privacy policy link
 
         DohEntry(String name, String template, String privacy) {
-            mName = name;
-            mTemplate = template;
-            mPrivacy = privacy;
+            this.name = name;
+            this.template = template;
+            this.privacy = privacy;
         }
 
         @Override
         public String toString() {
-            return mName;
+            return name;
         }
     }
 
@@ -368,7 +369,7 @@ public class PrivacyPreferencesManager implements CrashReportingPermissionManage
      *
      * @param mode The desired new Secure DNS mode.
      */
-    public void setSecureDnsModeMode(@SecureDnsMode int mode) {
+    public void setSecureDnsMode(@SecureDnsMode int mode) {
         PrivacyPreferencesManagerJni.get().setSecureDnsMode(mode);
     }
 
@@ -392,6 +393,10 @@ public class PrivacyPreferencesManager implements CrashReportingPermissionManage
     }
 
     /**
+     * Get the raw preference value, which can represent multiple templates separated
+     * by whitespace.  The raw value is needed in order to allow direct editing while
+     * preserving whitespace.
+     *
      * @return The templates (separated by spaces) of the DoH server
      *     currently selected for use in "secure" mode, or "" if there is none.
      */
@@ -425,7 +430,7 @@ public class PrivacyPreferencesManager implements CrashReportingPermissionManage
      */
     public void updateDohDropdownHistograms(DohEntry oldEntry, DohEntry newEntry) {
         PrivacyPreferencesManagerJni.get().updateDohDropdownHistograms(
-                oldEntry.mTemplate, newEntry.mTemplate);
+                oldEntry.template, newEntry.template);
     }
 
     /**

chrome/android/java/src/org/chromium/chrome/browser/privacy/settings/PrivacySettings.java

@@ -19,6 +19,7 @@ import org.chromium.chrome.R;
 import org.chromium.chrome.browser.help.HelpAndFeedback;
 import org.chromium.chrome.browser.preferences.Pref;
 import org.chromium.chrome.browser.preferences.PrefServiceBridge;
+import org.chromium.chrome.browser.privacy.settings.PrivacyPreferencesManager.DohEntry;
 import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.chrome.browser.settings.ChromeManagedPreferenceDelegate;
 import org.chromium.chrome.browser.settings.SettingsLauncher;
@@ -28,9 +29,12 @@ import org.chromium.chrome.browser.usage_stats.UsageStatsConsentDialog;
 import org.chromium.components.browser_ui.settings.ChromeBaseCheckBoxPreference;
 import org.chromium.components.browser_ui.settings.ManagedPreferenceDelegate;
 import org.chromium.components.browser_ui.settings.SettingsUtils;
+import org.chromium.net.SecureDnsMode;
 import org.chromium.ui.text.NoUnderlineClickableSpan;
 import org.chromium.ui.text.SpanApplier;
 
+import java.util.List;
+
 /**
  * Fragment to keep track of the all the privacy related preferences.
  */
@@ -38,6 +42,7 @@ public class PrivacySettings
         extends PreferenceFragmentCompat implements Preference.OnPreferenceChangeListener {
     private static final String PREF_CAN_MAKE_PAYMENT = "can_make_payment";
     private static final String PREF_NETWORK_PREDICTIONS = "preload_pages";
+    private static final String PREF_SECURE_DNS = "secure_dns";
     private static final String PREF_USAGE_STATS = "usage_stats_reporting";
     private static final String PREF_DO_NOT_TRACK = "do_not_track";
     private static final String PREF_SYNC_AND_SERVICES_LINK = "sync_and_services_link";
@@ -65,6 +70,9 @@ public class PrivacySettings
         networkPredictionPref.setOnPreferenceChangeListener(this);
         networkPredictionPref.setManagedPreferenceDelegate(mManagedPreferenceDelegate);
 
+        Preference secureDnsPref = findPreference(PREF_SECURE_DNS);
+        secureDnsPref.setVisible(privacyPrefManager.isDnsOverHttpsUiEnabled());
+
         Preference syncAndServicesLink = findPreference(PREF_SYNC_AND_SERVICES_LINK);
         NoUnderlineClickableSpan linkSpan = new NoUnderlineClickableSpan(getResources(), view -> {
             SettingsLauncher settingsLauncher = new SettingsLauncherImpl();
@@ -117,6 +125,31 @@ public class PrivacySettings
                             : R.string.text_off);
         }
 
+        Preference secureDnsPref = findPreference(PREF_SECURE_DNS);
+        if (secureDnsPref != null && secureDnsPref.isVisible()) {
+            PrivacyPreferencesManager manager = PrivacyPreferencesManager.getInstance();
+            @SecureDnsMode
+            int mode = manager.getSecureDnsMode();
+            if (mode == SecureDnsMode.OFF) {
+                secureDnsPref.setSummary(R.string.text_off);
+            } else if (mode == SecureDnsMode.AUTOMATIC) {
+                secureDnsPref.setSummary(R.string.settings_automatic_mode_summary);
+            } else {
+                String templateGroup = manager.getDnsOverHttpsTemplates();
+                List<DohEntry> providers = manager.getDohProviders();
+                String serverName = templateGroup;
+                for (int i = 0; i < providers.size(); i++) {
+                    DohEntry entry = providers.get(i);
+                    if (entry.template.equals(templateGroup)) {
+                        serverName = entry.name;
+                        break;
+                    }
+                }
+                secureDnsPref.setSummary(
+                        String.format("%s - %s", getString(R.string.text_on), serverName));
+            }
+        }
+
         Preference usageStatsPref = findPreference(PREF_USAGE_STATS);
         if (usageStatsPref != null) {
             if (BuildInfo.isAtLeastQ() && prefServiceBridge.getBoolean(Pref.USAGE_STATS_ENABLED)) {

chrome/android/java/src/org/chromium/chrome/browser/privacy/settings/SecureDnsProviderPreference.java

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.privacy.settings;
+
+import android.content.Context;
+import android.text.Editable;
+import android.text.Html;
+import android.text.TextWatcher;
+import android.text.method.LinkMovementMethod;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.AdapterView;
+import android.widget.ArrayAdapter;
+import android.widget.EditText;
+import android.widget.RadioGroup;
+import android.widget.Spinner;
+import android.widget.TextView;
+
+import androidx.annotation.NonNull;
+import androidx.preference.Preference;
+import androidx.preference.PreferenceViewHolder;
+
+import com.google.android.material.textfield.TextInputLayout;
+
+import org.chromium.chrome.R;
+import org.chromium.chrome.browser.privacy.settings.PrivacyPreferencesManager.DohEntry;
+import org.chromium.components.browser_ui.widget.RadioButtonWithDescription;
+import org.chromium.components.browser_ui.widget.RadioButtonWithDescriptionLayout;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * SecureDnsProviderPreference is the user interface that is shown when Secure DNS is enabled.
+ * When Secure DNS is disabled, the SecureDnsProviderPreference is hidden.
+ */
+public class SecureDnsProviderPreference
+        extends Preference implements RadioGroup.OnCheckedChangeListener,
+                                      AdapterView.OnItemSelectedListener, TextWatcher {
+    // UI strings, loaded from the context.
+    private final String mPrivacyTemplate;
+    private final String mInvalidWarning;
+    private final String mProbeWarning;
+
+    // Server menu entries.
+    private final List<DohEntry> mOptions;
+
+    // UI elements.  These fields are assigned only once, in onBindViewHolder.
+    private RadioButtonWithDescriptionLayout mGroup;
+    private RadioButtonWithDescription mAutomaticButton;
+    private RadioButtonWithDescription mSecureButton;
+    private Spinner mServerMenu;
+    private TextView mPrivacyPolicy;
+    private EditText mCustomServer;
+    private TextInputLayout mCustomServerLayout;
+
+    // All variable UI state for SecureDnsProviderPreference is encapsulated in this field.
+    // To ensure that the UI is updated whenever the state changes, this field
+    // should only be modified by setState().
+    private State mState;
+
+    // Checks whether the current template is actually reachable, and updates
+    // mCustomServerLayout's error state.
+    private final Runnable mProbeRunner = this::startServerProbe;
+
+    /**
+     * State is an immutable representation of the control's current UI state.  It can represent
+     * states that are invalid, which are required when editing the template or changing modes.
+     */
+    static class State {
+        // Indicates that secure mode is selected.
+        public final boolean secure;
+        // The selected or entered DoH template(s), if any.
+        public final @NonNull String template;
+        // Whether the selected template is valid.
+        public final boolean valid;
+
+        State(boolean secure, @NonNull String template, boolean valid) {
+            this.secure = secure;
+            this.template = template;
+            this.valid = valid;
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj instanceof State) {
+                State other = (State) obj;
+                return other.secure == secure && other.template.equals(template)
+                        && other.valid == valid;
+            }
+            return false;
+        }
+
+        @Override
+        public int hashCode() {
+            // This method is not used, but is defined here for consistency with equals().
+            return toString().hashCode();
+        }
+
+        State withSecure(boolean secure) {
+            return new State(secure, template, valid);
+        }
+
+        State withTemplate(@NonNull String template) {
+            return new State(secure, template, valid);
+        }
+
+        State withValid(boolean valid) {
+            return new State(secure, template, valid);
+        }
+
+        @Override
+        public @NonNull String toString() {
+            return String.format("State(%b, %s, %b)", secure, template, valid);
+        }
+    }
+
+    public SecureDnsProviderPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        // Inflating from XML.
+        setLayoutResource(R.layout.secure_dns_provider_preference);
+
+        // Preload strings from disk.
+        mPrivacyTemplate = context.getString(R.string.settings_secure_dropdown_mode_privacy_policy);
+        mInvalidWarning = context.getString(R.string.settings_secure_dns_custom_format_error);
+        mProbeWarning = context.getString(R.string.settings_secure_dns_custom_connection_error);
+        mOptions = makeOptions(context);
+    }
+
+    private static List<DohEntry> makeOptions(Context context) {
+        List<DohEntry> entries = PrivacyPreferencesManager.getInstance().getDohProviders();
+
+        // The Spinner's options consist of an entry called "Custom", followed
+        // by the providers in random order.
+        List<DohEntry> options = new ArrayList<>(entries.size() + 1);
+        String customEntryName = context.getString(R.string.settings_custom);
+        options.add(new DohEntry(customEntryName, "", ""));
+        Collections.shuffle(entries);
+        options.addAll(entries);
+
+        return options;
+    }
+
+    @Override
+    public void onBindViewHolder(PreferenceViewHolder holder) {
+        super.onBindViewHolder(holder);
+        mGroup = (RadioButtonWithDescriptionLayout) holder.findViewById(R.id.mode_group);
+        mGroup.setOnCheckedChangeListener(this);
+        mAutomaticButton = (RadioButtonWithDescription) holder.findViewById(R.id.automatic);
+        mSecureButton = (RadioButtonWithDescription) holder.findViewById(R.id.secure);
+
+        View selectionContainer = holder.findViewById(R.id.selection_container);
+        mServerMenu = selectionContainer.findViewById(R.id.dropdown_spinner);
+        mServerMenu.setOnItemSelectedListener(this);
+        Context context = selectionContainer.getContext();
+        ArrayAdapter<DohEntry> adapter =
+                new ArrayAdapter<>(context, R.layout.secure_dns_provider_spinner_item, mOptions);
+        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
+        mServerMenu.setAdapter(adapter);
+
+        mPrivacyPolicy = selectionContainer.findViewById(R.id.privacy_policy);
+        mPrivacyPolicy.setMovementMethod(LinkMovementMethod.getInstance());
+        mCustomServer = selectionContainer.findViewById(R.id.custom_server);
+        mCustomServer.addTextChangedListener(this);
+        mCustomServerLayout = selectionContainer.findViewById(R.id.custom_server_layout);
+
+        mGroup.attachAccessoryView(selectionContainer, mSecureButton);
+        updateView();
+    }
+
+    public void setState(State state) {
+        if (!state.equals(mState)) {
+            mState = state;
+            updateView();
+        }
+    }
+
+    public State getState() {
+        return mState;
+    }
+
+    // Returns the index of the dropdown entry that matches the current template,
+    // or 0 if none match (i.e. a custom template).
+    private int matchingDropdownIndex() {
+        for (int i = 1; i < mServerMenu.getCount(); ++i) {
+            DohEntry entry = (DohEntry) mServerMenu.getItemAtPosition(i);
+            if (entry.template.equals(mState.template)) {
+                return i;
+            }
+        }
+        return 0;
+    }
+
+    /**
+     * Updates the view to match mState.
+     */
+    private void updateView() {
+        if (mGroup == null) {
+            // Not yet bound to view holder.
+            return;
+        }
+
+        if (mSecureButton.isChecked() != mState.secure) {
+            mSecureButton.setChecked(mState.secure);
+        }
+        boolean automaticMode = !mState.secure;
+        if (mAutomaticButton.isChecked() != automaticMode) {
+            mAutomaticButton.setChecked(automaticMode);
+        }
+
+        int position = matchingDropdownIndex();
+        if (mServerMenu.getSelectedItemPosition() != position) {
+            mServerMenu.setSelection(position);
+        }
+
+        // Position 0 is the custom server.  Other positions are actual server entries.
+        if (position > 0) {
+            // Selected server mode.
+            DohEntry entry = (DohEntry) mServerMenu.getSelectedItem();
+            String html = mPrivacyTemplate.replace("$1", entry.privacy);
+            mPrivacyPolicy.setText(Html.fromHtml(html));
+
+            mPrivacyPolicy.setVisibility(View.VISIBLE);
+            mCustomServerLayout.setVisibility(View.GONE);
+        } else {
+            // Custom server mode.
+            if (!mCustomServer.getText().toString().equals(mState.template)) {
+                mCustomServer.setText(mState.template);
+                mCustomServer.removeCallbacks(mProbeRunner);
+                if (mState.secure) {
+                    mCustomServer.requestFocus();
+
+                    // If the custom server field is idle for one second, run a probe.
+                    // Any changes to the field will cancel this probe and start another.
+                    mCustomServer.postDelayed(mProbeRunner, 1000);
+                }
+            }
+
+            // Show a warning if the input is invalid and is not the start of a valid URL.
+            boolean showWarning = !mState.valid && !"https://".startsWith(mState.template);
+            mCustomServerLayout.setError(showWarning ? mInvalidWarning : null);
+
+            mCustomServerLayout.setVisibility(mState.secure ? View.VISIBLE : View.INVISIBLE);
+            mPrivacyPolicy.setVisibility(View.GONE);
+        }
+
+        PrivacyPreferencesManager.getInstance().updateDohValidationHistogram(mState.valid);
+    }
+
+    private void startServerProbe() {
+        String group = mState.template;
+        if (group.isEmpty() || !mState.valid || !mState.secure) {
+            return;
+        }
+        // probeDohServer() is a blocking network call that uses WaitableEvent, so it cannot run
+        // on the UI thread, nor via the Java PostTask bindings, which do not expose
+        // base::WithBaseSyncPrimitives.  Instead, it runs on a fresh Java thread.
+        new Thread(() -> {
+            PrivacyPreferencesManager manager = PrivacyPreferencesManager.getInstance();
+            for (String template : manager.splitDohTemplateGroup(group)) {
+                if (manager.probeDohServer(template)) {
+                    return;
+                }
+            }
+            mCustomServer.post(() -> { // Send the state change back to the UI thread.
+                // Check that the setting hasn't been changed.
+                if (mState.template.contentEquals(group)) {
+                    mCustomServerLayout.setError(mProbeWarning);
+                }
+            });
+        }).start();
+    }
+
+    @Override
+    public void onCheckedChanged(RadioGroup group, int checkedId) {
+        boolean secure = checkedId == R.id.secure;
+        if (mState.secure != secure) {
+            tryUpdate(mState.withSecure(secure));
+        }
+    }
+
+    @Override
+    public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
+        int oldPos = matchingDropdownIndex();
+        if (oldPos == pos) {
+            // This is the same item that was already in effect.  Ignore spurious event.
+            // This check is required to avoid overwriting the custom template, because
+            // attaching an adapter triggers a spurious onItemSelected event.
+            return;
+        }
+        DohEntry oldEntry = (DohEntry) parent.getItemAtPosition(oldPos);
+        DohEntry entry = (DohEntry) parent.getItemAtPosition(pos);
+        tryUpdate(mState.withTemplate(entry.template));
+
+        PrivacyPreferencesManager.getInstance().updateDohDropdownHistograms(oldEntry, entry);
+    }
+
+    @Override
+    public void onNothingSelected(AdapterView<?> parent) {
+        // In this UI, one radio button is always selected.
+    }
+
+    private void tryUpdate(State newState) {
+        if (callChangeListener(newState)) {
+            setState(newState);
+        } else {
+            updateView();
+        }
+    }
+
+    @Override
+    public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
+
+    @Override
+    public void onTextChanged(CharSequence s, int start, int count, int after) {}
+
+    @Override
+    public void afterTextChanged(Editable s) {
+        tryUpdate(mState.withTemplate(s.toString()));
+
+        mCustomServer.removeCallbacks(mProbeRunner);
+        mCustomServer.postDelayed(mProbeRunner, 1000);
+    }
+}

chrome/android/java/src/org/chromium/chrome/browser/privacy/settings/SecureDnsSettings.java

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.privacy.settings;
+
+import android.os.Bundle;
+
+import androidx.preference.PreferenceFragmentCompat;
+
+import org.chromium.chrome.R;
+import org.chromium.chrome.browser.net.SecureDnsManagementMode;
+import org.chromium.chrome.browser.privacy.settings.SecureDnsProviderPreference.State;
+import org.chromium.chrome.browser.settings.ChromeManagedPreferenceDelegate;
+import org.chromium.components.browser_ui.settings.ChromeSwitchPreference;
+import org.chromium.components.browser_ui.settings.SettingsUtils;
+import org.chromium.net.SecureDnsMode;
+
+/**
+ * Fragment to manage Secure DNS preference.  It consists of a toggle switch and,
+ * if the switch is enabled, a SecureDnsControl.
+ */
+public class SecureDnsSettings extends PreferenceFragmentCompat {
+    // Must match keys in secure_dns_settings.xml.
+    private static final String PREF_SECURE_DNS_SWITCH = "secure_dns_switch";
+    private static final String PREF_SECURE_DNS_PROVIDER = "secure_dns_provider";
+
+    private PrivacyPreferencesManager mManager;
+    private ChromeSwitchPreference mSecureDnsSwitch;
+    private SecureDnsProviderPreference mSecureDnsProviderPreference;
+
+    @Override
+    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
+        getActivity().setTitle(R.string.settings_secure_dns_title);
+        SettingsUtils.addPreferencesFromResource(this, R.xml.secure_dns_settings);
+
+        mManager = PrivacyPreferencesManager.getInstance();
+
+        // Set up preferences inside the activity.
+        mSecureDnsSwitch = (ChromeSwitchPreference) findPreference(PREF_SECURE_DNS_SWITCH);
+        mSecureDnsSwitch.setManagedPreferenceDelegate(
+                (ChromeManagedPreferenceDelegate) preference -> mManager.isSecureDnsModeManaged());
+        mSecureDnsSwitch.setOnPreferenceChangeListener((preference, enabled) -> {
+            storePreferenceState((boolean) enabled, mSecureDnsProviderPreference.getState());
+            loadPreferenceState();
+            return true;
+        });
+
+        if (!mManager.isSecureDnsModeManaged()) {
+            // If the mode isn't managed directly, we still need to disable the controls
+            // if we detect a managed system configuration, or any parental control software.
+            // However, we don't want to show the managed setting icon in this case, because the
+            // setting is not directly controlled by a policy.
+            @SecureDnsManagementMode
+            int managementMode = mManager.getSecureDnsManagementMode();
+            if (managementMode != SecureDnsManagementMode.NO_OVERRIDE) {
+                mSecureDnsSwitch.setEnabled(false);
+                boolean parentalControls =
+                        managementMode == SecureDnsManagementMode.DISABLED_PARENTAL_CONTROLS;
+                mSecureDnsSwitch.setSummaryOff(parentalControls
+                                ? R.string.settings_secure_dns_disabled_for_parental_control
+                                : R.string.settings_secure_dns_disabled_for_managed_environment);
+            }
+        }
+
+        mSecureDnsProviderPreference =
+                (SecureDnsProviderPreference) findPreference(PREF_SECURE_DNS_PROVIDER);
+        mSecureDnsProviderPreference.setOnPreferenceChangeListener((preference, value) -> {
+            State controlState = (State) value;
+            boolean valid = storePreferenceState(mSecureDnsSwitch.isChecked(), controlState);
+            if (valid != controlState.valid) {
+                mSecureDnsProviderPreference.setState(controlState.withValid(valid));
+                // Cancel the change to controlState.
+                return false;
+            }
+            return true;
+        });
+
+        // Update preference views and state.
+        loadPreferenceState();
+    }
+
+    /**
+     * @param enabled Whether the toggle switch is enabled
+     * @param controlState The state from SecureDnsControl.
+     * @return True if the state was successfully stored.
+     */
+    private boolean storePreferenceState(boolean enabled, State controlState) {
+        if (!enabled) {
+            mManager.setSecureDnsMode(SecureDnsMode.OFF);
+            mManager.setDnsOverHttpsTemplates("");
+        } else if (!controlState.secure) {
+            mManager.setSecureDnsMode(SecureDnsMode.AUTOMATIC);
+            mManager.setDnsOverHttpsTemplates("");
+        } else {
+            if (controlState.template.isEmpty()
+                    || !mManager.setDnsOverHttpsTemplates(controlState.template)) {
+                return false;
+            }
+            mManager.setSecureDnsMode(SecureDnsMode.SECURE);
+        }
+        return true;
+    }
+
+    private void loadPreferenceState() {
+        @SecureDnsMode
+        int mode = mManager.getSecureDnsMode();
+        boolean enabled = mode != SecureDnsMode.OFF;
+        boolean enforced = mManager.isSecureDnsModeManaged()
+                || mManager.getSecureDnsManagementMode() != SecureDnsManagementMode.NO_OVERRIDE;
+        mSecureDnsSwitch.setChecked(enabled);
+        mSecureDnsProviderPreference.setEnabled(enabled && !enforced);
+
+        boolean secure = mode == SecureDnsMode.SECURE;
+        String template = mManager.getDnsOverHttpsTemplates();
+        boolean valid = true; // States loaded from storage are presumed valid.
+        mSecureDnsProviderPreference.setState(new State(secure, template, valid));
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        loadPreferenceState();
+    }
+}

chrome/browser/ui/android/strings/android_chrome_strings.grd

@@ -726,6 +726,45 @@ For example, some websites may respond to this request by showing you ads that a
       <message name="IDS_CAN_MAKE_PAYMENT_TITLE" desc="Title for preference to allow websites to know whether you have payment methods available through PaymentRequest.CanMakePayment interface">
         Access payment methods
       </message>
+      <message name="IDS_SETTINGS_CUSTOM" desc="Label for a custom option in a dropdown menu.">
+        Custom
+      </message>
+      <message name="IDS_SETTINGS_SECURE_DNS_TITLE" desc="Title of the Secure DNS settings option">
+        Use secure DNS
+      </message>
+      <message name="IDS_SETTINGS_SECURE_DNS_DESCRIPTION" desc="Secondary, continued explanation of secure DNS in Privacy options">
+        Determines how to connect to websites over a secure connection
+      </message>
+      <message name="IDS_SETTINGS_AUTOMATIC_MODE_LABEL" desc="Text of the radio button that puts secure DNS in auto-upgrade mode">
+        Use your current service provider
+      </message>
+      <message name="IDS_SETTINGS_AUTOMATIC_MODE_DESCRIPTION" desc="Descriptive text that appears below IDS_SETTINGS_AUTOMATIC_MODE_LABEL.">
+        Secure DNS may not be available all the time
+      </message>
+      <message name="IDS_SETTINGS_AUTOMATIC_MODE_SUMMARY" desc="Short description of automatic mode">
+        Automatic
+      </message>
+      <message name="IDS_SETTINGS_SECURE_DROPDOWN_MODE_DESCRIPTION" desc="Text of the radio button that allows a secure resolver to be selected from a dropdown menu">
+        Choose another provider:
+      </message>
+      <message name="IDS_SETTINGS_SECURE_DROPDOWN_MODE_PRIVACY_POLICY" desc="Text that displays a link to the privacy policy of the resolver selected from a dropdown menu">
+        See this provider's <ph name="BEGIN_LINK">&lt;a target="_blank" href="$1<ex>https://google.com/</ex>"&gt;</ph>privacy policy<ph name="END_LINK">&lt;/a&gt;</ph>
+      </message>
+      <message name="IDS_SETTINGS_SECURE_DNS_DISABLED_FOR_MANAGED_ENVIRONMENT" desc="Substring of the secure DNS setting when secure DNS is disabled due to detection of a managed environment">
+        This setting is disabled on managed browsers
+      </message>
+      <message name="IDS_SETTINGS_SECURE_DNS_DISABLED_FOR_PARENTAL_CONTROL" desc="Substring of the secure DNS setting when secure DNS is disabled due to detection of OS-level parental controls">
+        This setting is disabled because parental controls are on
+      </message>
+      <message name="IDS_SETTINGS_SECURE_DNS_CUSTOM_PLACEHOLDER" desc="Placeholder text for a textbox where users can enter a custom secure DNS provider">
+        Provider URL
+      </message>
+      <message name="IDS_SETTINGS_SECURE_DNS_CUSTOM_FORMAT_ERROR" desc="Error text for an incorrectly formatted entry for the custom secure DNS provider">
+        Enter a correctly formatted URL
+      </message>
+      <message name="IDS_SETTINGS_SECURE_DNS_CUSTOM_CONNECTION_ERROR" desc="Error text for a custom secure DNS provider entry to which a probe connection fails">
+        Please verify that this is a valid provider or try again later
+      </message>
       <message name="IDS_CLEAR_BROWSING_DATA_TITLE" desc="Title of the Clear Browsing Data screen. [CHAR-LIMIT=32]">
         Clear browsing data
       </message>

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_SETTINGS_AUTOMATIC_MODE_DESCRIPTION.png.sha1

+07470847c57193b5abe3c19d409f40fe03c64ac4
\ No newline at end of file

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_SETTINGS_AUTOMATIC_MODE_LABEL.png.sha1

+07470847c57193b5abe3c19d409f40fe03c64ac4
\ No newline at end of file

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_SETTINGS_AUTOMATIC_MODE_SUMMARY.png.sha1

+18e467edce1b013c204d1b05cbab76f0790f6ffc
\ No newline at end of file

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_SETTINGS_CUSTOM.png.sha1

+07470847c57193b5abe3c19d409f40fe03c64ac4
\ No newline at end of file

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_SETTINGS_SECURE_DNS_CUSTOM_CONNECTION_ERROR.png.sha1

+6e5e2c36f636ad3c56ffc05b07f0c72cb2815d1d
\ No newline at end of file

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_SETTINGS_SECURE_DNS_CUSTOM_FORMAT_ERROR.png.sha1

+6e7270e55d3aeb461293fd56328e1b4b2c2bdf8c
\ No newline at end of file

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_SETTINGS_SECURE_DNS_CUSTOM_PLACEHOLDER.png.sha1

+6e5e2c36f636ad3c56ffc05b07f0c72cb2815d1d
\ No newline at end of file

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_SETTINGS_SECURE_DNS_DESCRIPTION.png.sha1

+07470847c57193b5abe3c19d409f40fe03c64ac4
\ No newline at end of file

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_SETTINGS_SECURE_DNS_DISABLED_FOR_MANAGED_ENVIRONMENT.png.sha1

+1f68aa0e6cde6412beda4ecde3c51321e61f9b9d
\ No newline at end of file

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_SETTINGS_SECURE_DNS_DISABLED_FOR_PARENTAL_CONTROL.png.sha1

+5ddd6edf519ba9f998bf8bd8c76af426a14787f2
\ No newline at end of file

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_SETTINGS_SECURE_DNS_TITLE.png.sha1

+864e7cae4749082cf375f59b5f80b7a1bbcc3544
\ No newline at end of file

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_SETTINGS_SECURE_DROPDOWN_MODE_DESCRIPTION.png.sha1

+6e5e2c36f636ad3c56ffc05b07f0c72cb2815d1d
\ No newline at end of file

chrome/browser/ui/android/strings/android_chrome_strings_grd/IDS_SETTINGS_SECURE_DROPDOWN_MODE_PRIVACY_POLICY.png.sha1

+482e40ac429630882ac8adb82df65c7fd6ca0bda
\ No newline at end of file