bromite/build/patches/Add-user-setting-for-DNS-over-HTTPS-DoH-custom-URL.patch

From: csagan5 <32685696+csagan5@users.noreply.github.com>
Date: Sat, 23 Nov 2019 10:55:16 +0100
Subject: Add user setting for DNS-over-HTTPS (DoH) custom URL

---
 chrome/android/chrome_java_sources.gni        |  2 +
 chrome/android/java/res/layout/doh_editor.xml | 65 +++++++++++++
 chrome/android/java/res/values/values.xml     |  2 +
 .../android/java/res/xml/doh_preferences.xml  | 25 +++++
 .../java/res/xml/privacy_preferences.xml      |  5 +
 .../browser/flags/FeatureUtilities.java       | 24 +++++
 .../chrome/browser/settings/DoHEditor.java    | 92 +++++++++++++++++++
 .../browser/settings/DoHPreferences.java      | 54 +++++++++++
 chrome/app/generated_resources.grd            |  6 ++
 chrome/browser/android/feature_utilities.cc   | 23 +++++
 .../net/system_network_context_manager.cc     | 46 +++-------
 .../strings/android_chrome_strings.grd        | 11 +++
 chrome/common/chrome_features.cc              |  4 +-
 13 files changed, 322 insertions(+), 37 deletions(-)
 create mode 100644 chrome/android/java/res/layout/doh_editor.xml
 create mode 100644 chrome/android/java/res/xml/doh_preferences.xml
 create mode 100644 chrome/android/java/src/org/chromium/chrome/browser/settings/DoHEditor.java
 create mode 100644 chrome/android/java/src/org/chromium/chrome/browser/settings/DoHPreferences.java

diff --git a/chrome/android/chrome_java_sources.gni b/chrome/android/chrome_java_sources.gni
--- a/chrome/android/chrome_java_sources.gni
+++ b/chrome/android/chrome_java_sources.gni
@@ -1335,6 +1335,8 @@ chrome_java_sources = [
   "java/src/org/chromium/chrome/browser/settings/ChromeSwitchPreference.java",
   "java/src/org/chromium/chrome/browser/settings/ClearBrowsingDataCheckBoxPreference.java",
   "java/src/org/chromium/chrome/browser/settings/ExpandablePreferenceGroup.java",
+  "java/src/org/chromium/chrome/browser/settings/DoHEditor.java",
+  "java/src/org/chromium/chrome/browser/settings/DoHPreferences.java",
   "java/src/org/chromium/chrome/browser/settings/HomepageEditor.java",
   "java/src/org/chromium/chrome/browser/settings/HomepagePreferences.java",
   "java/src/org/chromium/chrome/browser/settings/HyperlinkPreference.java",
diff --git a/chrome/android/java/res/layout/doh_editor.xml b/chrome/android/java/res/layout/doh_editor.xml
new file mode 100644
--- /dev/null
+++ b/chrome/android/java/res/layout/doh_editor.xml
@@ -0,0 +1,65 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2015 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. -->
+
+<FrameLayout
+    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" >
+
+    <ScrollView
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:id="@+id/scroll_view"
+        android:fillViewport="true" >
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:focusableInTouchMode="true" >
+
+            <org.chromium.chrome.browser.widget.ChromeTextInputLayout
+                android:id="@+id/doh_url"
+                style="@style/PreferenceScreenLayout"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content" >
+                <!-- TODO(crbug.com/900912): Fix and remove lint ignore -->
+                <EditText
+                    tools:ignore="Autofill"
+                    android:id="@+id/doh_url_edit"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:inputType="textUri"
+                    android:singleLine="true"
+                    android:hint="@string/options_doh_edit_label" />
+            </org.chromium.chrome.browser.widget.ChromeTextInputLayout>
+
+            <Space style="@style/ButtonBarTopSpacer" />
+            <View style="@style/ButtonBarTopDivider" />
+
+            <LinearLayout style="@style/ButtonBar" >
+                <org.chromium.ui.widget.ButtonCompat
+                    android:id="@+id/doh_reset"
+                    style="@style/ButtonBarButton"
+                    android:text="@string/reset" />
+
+                <org.chromium.ui.widget.ButtonCompat
+                    android:id="@+id/doh_cancel"
+                    style="@style/ButtonBarButton"
+                    android:text="@string/cancel" />
+
+                <org.chromium.ui.widget.ButtonCompat
+                    android:id="@+id/doh_save"
+                    style="@style/ButtonBarButton"
+                    android:text="@string/save" />
+            </LinearLayout>
+        </LinearLayout>
+    </ScrollView>
+
+    <include layout="@layout/preferences_action_bar_shadow"/>
+
+</FrameLayout>
diff --git a/chrome/android/java/res/values/values.xml b/chrome/android/java/res/values/values.xml
--- a/chrome/android/java/res/values/values.xml
+++ b/chrome/android/java/res/values/values.xml
@@ -91,6 +91,8 @@
     <integer name="download_infobar_bar_fill_in_delay">400</integer>
     <integer name="download_infobar_bar_fill_out_delay">200</integer>
 
+    <string name="doh_help_url">https://www.bromite.org/doh</string>
+
     <!-- Bottom navigation bar styling. -->
     <bool name="window_light_navigation_bar">true</bool>
 
diff --git a/chrome/android/java/res/xml/doh_preferences.xml b/chrome/android/java/res/xml/doh_preferences.xml
new file mode 100644
--- /dev/null
+++ b/chrome/android/java/res/xml/doh_preferences.xml
@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2015 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"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <org.chromium.chrome.browser.settings.ChromeSwitchPreference
+        android:key="doh_switch"
+        android:summaryOn="@string/text_on"
+        android:summaryOff="@string/text_off" />
+
+    <org.chromium.chrome.browser.settings.HyperlinkPreference
+        android:key="doh_help"
+        android:title="@string/doh_help"
+        app:url="@string/doh_help_url" />
+
+    <Preference
+        android:key="doh_edit"
+        android:title="@string/options_doh_edit_label"
+        android:fragment="org.chromium.chrome.browser.settings.DoHEditor" />
+
+</PreferenceScreen>
diff --git a/chrome/android/java/res/xml/privacy_preferences.xml b/chrome/android/java/res/xml/privacy_preferences.xml
--- a/chrome/android/java/res/xml/privacy_preferences.xml
+++ b/chrome/android/java/res/xml/privacy_preferences.xml
@@ -19,6 +19,11 @@
         android:key="can_make_payment"
         android:title="@string/can_make_payment_title"
         android:summary="@string/settings_can_make_payment_toggle_label" />
+    <Preference
+        android:fragment="org.chromium.chrome.browser.settings.DoHPreferences"
+        android:key="doh"
+        android:title="@string/options_doh_title"
+        android:summary="@string/options_doh_summary" />
     <org.chromium.chrome.browser.settings.ChromeBaseCheckBoxPreference
         android:key="preload_pages"
         android:title="@string/preload_pages_title"
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/flags/FeatureUtilities.java b/chrome/android/java/src/org/chromium/chrome/browser/flags/FeatureUtilities.java
--- a/chrome/android/java/src/org/chromium/chrome/browser/flags/FeatureUtilities.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/flags/FeatureUtilities.java
@@ -95,6 +95,26 @@ public class FeatureUtilities {
         FeatureUtilitiesJni.get().setCustomTabVisible(visible);
     }
 
+     /**
+     * Records whether custom URL for DoH is enabled with native-side feature utilities.
+     * @param url Whether custom URL is enabled or not.
+     */
+     public static void setDoHEnabled(boolean enabled) {
+         FeatureUtilitiesJni.get().setDoHEnabled(enabled);
+     }
+
+     public static boolean getDoHEnabled() {
+         return FeatureUtilitiesJni.get().getDoHEnabled();
+     }
+
+     public static void setDoHTemplates(String t) {
+         FeatureUtilitiesJni.get().setDoHTemplates(t);
+     }
+
+     public static String getDoHTemplates() {
+         return FeatureUtilitiesJni.get().getDoHTemplates();
+     }
+
     /**
      * Records whether the activity is in multi-window mode with native-side feature utilities.
      * @param isInMultiWindowMode Whether the activity is in Android N multi-window mode.
@@ -736,6 +756,10 @@ public class FeatureUtilities {
         void setCustomTabVisible(boolean visible);
         void setActivityType(@ActivityType int type);
         void setIsInMultiWindowMode(boolean isInMultiWindowMode);
+        void setDoHEnabled(boolean enabled);
+        boolean getDoHEnabled();
+        void setDoHTemplates(String templates);
+        String getDoHTemplates();
         boolean isNetworkServiceWarmUpEnabled();
         void setAdBlockFiltersURL(String url);
         String getAdBlockFiltersURL();
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/settings/DoHEditor.java b/chrome/android/java/src/org/chromium/chrome/browser/settings/DoHEditor.java
new file mode 100644
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/settings/DoHEditor.java
@@ -0,0 +1,92 @@
+// Copyright 2015 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.settings;
+
+import android.os.Bundle;
+import android.support.v4.app.Fragment;
+import android.text.Editable;
+import android.text.TextWatcher;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+import android.widget.EditText;
+
+import org.chromium.chrome.browser.settings.SettingsUtils;
+import org.chromium.chrome.browser.flags.FeatureUtilities;
+import org.chromium.chrome.R;
+import org.chromium.components.url_formatter.UrlFormatter;
+
+/**
+ * Provides the Java-UI for editing the DNS-over-HTTPS (DoH) preference.
+ */
+public class DoHEditor extends Fragment implements TextWatcher {
+    private EditText mDoHUrlEdit;
+    private Button mSaveButton;
+    private Button mResetButton;
+
+    @Override
+    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+            Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        getActivity().setTitle(R.string.options_doh_edit_title);
+
+        View v = inflater.inflate(R.layout.doh_editor, container, false);
+        View scrollView = v.findViewById(R.id.scroll_view);
+        scrollView.getViewTreeObserver().addOnScrollChangedListener(
+                SettingsUtils.getShowShadowOnScrollListener(v, v.findViewById(R.id.shadow)));
+        mDoHUrlEdit = (EditText) v.findViewById(R.id.doh_url_edit);
+        mDoHUrlEdit.setText(FeatureUtilities.getDoHTemplates());
+        mDoHUrlEdit.addTextChangedListener(this);
+        mDoHUrlEdit.requestFocus();
+
+        initializeSaveCancelResetButtons(v);
+        return v;
+    }
+
+    @Override
+    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+    }
+
+    @Override
+    public void onTextChanged(CharSequence s, int start, int before, int count) {
+        mSaveButton.setEnabled(s.length() != 0);
+        mResetButton.setEnabled(true);
+    }
+
+    @Override
+    public void afterTextChanged(Editable s) {
+    }
+
+    private void initializeSaveCancelResetButtons(View v) {
+        mResetButton = (Button) v.findViewById(R.id.doh_reset);
+        mResetButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                mDoHUrlEdit.setText(FeatureUtilities.getDoHTemplates());
+                getActivity().finish();
+            }
+        });
+
+        mSaveButton = (Button) v.findViewById(R.id.doh_save);
+        mSaveButton.setEnabled(false);
+        mSaveButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                FeatureUtilities.setDoHTemplates(
+                        mDoHUrlEdit.getText().toString());
+                getActivity().finish();
+            }
+        });
+
+        Button button = (Button) v.findViewById(R.id.doh_cancel);
+        button.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                getActivity().finish();
+            }
+        });
+    }
+}
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/settings/DoHPreferences.java b/chrome/android/java/src/org/chromium/chrome/browser/settings/DoHPreferences.java
new file mode 100644
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/settings/DoHPreferences.java
@@ -0,0 +1,54 @@
+// Copyright 2015 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.settings;
+
+import android.os.Bundle;
+import android.support.v7.preference.Preference;
+import android.support.v7.preference.PreferenceFragmentCompat;
+import org.chromium.chrome.browser.settings.ChromeSwitchPreference;
+
+import org.chromium.chrome.browser.settings.SettingsUtils;
+import org.chromium.chrome.browser.flags.FeatureUtilities;
+import androidx.annotation.VisibleForTesting;
+import org.chromium.chrome.R;
+
+/**
+ * Fragment that allows the user to configure DoH related preferences.
+ */
+public class DoHPreferences extends PreferenceFragmentCompat {
+    @VisibleForTesting
+    public static final String PREF_DOH_SWITCH = "doh_switch";
+    private static final String PREF_DOH_EDIT = "doh_edit";
+
+    private Preference mDoHEdit;
+
+    @Override
+    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
+        getActivity().setTitle(R.string.options_doh_title);
+        SettingsUtils.addPreferencesFromResource(this, R.xml.doh_preferences);
+
+        ChromeSwitchPreference mDoHSwitch =
+                (ChromeSwitchPreference) findPreference(PREF_DOH_SWITCH);
+        boolean isDoHEnabled = FeatureUtilities.getDoHEnabled();
+        mDoHSwitch.setChecked(isDoHEnabled);
+        mDoHSwitch.setOnPreferenceChangeListener((preference, newValue) -> {
+            FeatureUtilities.setDoHEnabled((boolean) newValue);
+            return true;
+        });
+
+        mDoHEdit = findPreference(PREF_DOH_EDIT);
+        updateCurrentDoHUrl();
+    }
+
+    private void updateCurrentDoHUrl() {
+        mDoHEdit.setSummary(FeatureUtilities.getDoHTemplates());
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        updateCurrentDoHUrl();
+    }
+}
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -6699,6 +6699,12 @@ the Bookmarks menu.">
         <message name="IDS_OPTIONS_HOMEPAGE_TITLE" desc="The title of the home page overlay on Android" formatter_data="android_java">
           Home page
         </message>
+        <message name="IDS_OPTIONS_DOH_TITLE" desc="The title of the DNS-over-HTTPS option on Android" formatter_data="android_java">
+          Secure DNS
+        </message>
+        <message name="IDS_OPTIONS_DOH_SUMMARY" desc="The title of the DNS-over-HTTPS summary on Android" formatter_data="android_java">
+          Configure DNS-over-HTTPS (DoH) secure DNS
+        </message>
       </if>
 
       <!-- Autofill dialog: field labels. -->
diff --git a/chrome/browser/android/feature_utilities.cc b/chrome/browser/android/feature_utilities.cc
--- a/chrome/browser/android/feature_utilities.cc
+++ b/chrome/browser/android/feature_utilities.cc
@@ -7,6 +7,9 @@
 #include "chrome/android/chrome_jni_headers/FeatureUtilities_jni.h"
 
 #include "base/android/jni_string.h"
+#include "chrome/browser/browser_process.h"
+#include "components/prefs/pref_service.h"
+#include "chrome/common/pref_names.h"
 #include "chrome/browser/ntp_snippets/content_suggestions_service_factory.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "components/ntp_snippets/content_suggestions_service.h"
@@ -87,3 +90,23 @@ static jboolean JNI_FeatureUtilities_IsNetworkServiceWarmUpEnabled(
   return content::IsOutOfProcessNetworkService() &&
          base::FeatureList::IsEnabled(features::kWarmUpNetworkProcess);
 }
+
+static jboolean JNI_FeatureUtilities_GetDoHEnabled(JNIEnv* env) {
+  std::string doh_mode = g_browser_process->local_state()->GetString(prefs::kDnsOverHttpsMode);
+  return ((doh_mode == "secure") || (doh_mode == "auto"));
+}
+
+static void JNI_FeatureUtilities_SetDoHEnabled(JNIEnv* env, jboolean enabled) {
+  if (enabled)
+    g_browser_process->local_state()->SetString(prefs::kDnsOverHttpsMode, "secure");
+  else
+    g_browser_process->local_state()->SetString(prefs::kDnsOverHttpsMode, "off");
+}
+
+static ScopedJavaLocalRef<jstring> JNI_FeatureUtilities_GetDoHTemplates(JNIEnv* env) {
+  return base::android::ConvertUTF8ToJavaString(env, g_browser_process->local_state()->GetString(prefs::kDnsOverHttpsTemplates));
+}
+
+static void JNI_FeatureUtilities_SetDoHTemplates(JNIEnv* env, const JavaParamRef<jstring>& templates) {
+  g_browser_process->local_state()->SetString(prefs::kDnsOverHttpsTemplates, base::android::ConvertJavaStringToUTF8(env, templates));
+}
diff --git a/chrome/browser/net/system_network_context_manager.cc b/chrome/browser/net/system_network_context_manager.cc
--- a/chrome/browser/net/system_network_context_manager.cc
+++ b/chrome/browser/net/system_network_context_manager.cc
@@ -139,9 +139,14 @@ void GetStubResolverConfig(
 
   std::string doh_templates =
       local_state->GetString(prefs::kDnsOverHttpsTemplates);
-  std::string server_method;
-  if (!doh_templates.empty() &&
-      *secure_dns_mode != net::DnsConfig::SecureDnsMode::OFF) {
+  if (doh_templates.empty()) {
+    *secure_dns_mode = net::DnsConfig::SecureDnsMode::OFF;
+    doh_mode = chrome_browser_net::kDnsOverHttpsModeOff;
+  }
+
+  LOG(INFO) << "DoH templates: '" << doh_templates << "' with mode " << doh_mode;
+  if (*secure_dns_mode != net::DnsConfig::SecureDnsMode::OFF) {
+    std::string server_method;
     for (const std::string& server_template :
          SplitString(doh_templates, " ", base::TRIM_WHITESPACE,
                      base::SPLIT_WANT_NONEMPTY)) {
@@ -429,40 +434,11 @@ SystemNetworkContextManager::SystemNetworkContextManager(
   // features before registering change callbacks for these preferences.
   local_state_->SetDefaultPrefValue(prefs::kBuiltInDnsClientEnabled,
                                     base::Value(ShouldEnableAsyncDns()));
-  std::string default_doh_mode = chrome_browser_net::kDnsOverHttpsModeOff;
-  std::string default_doh_templates = "";
-  if (base::FeatureList::IsEnabled(features::kDnsOverHttps)) {
-    if (features::kDnsOverHttpsFallbackParam.Get()) {
-      default_doh_mode = chrome_browser_net::kDnsOverHttpsModeAutomatic;
-    } else {
-      default_doh_mode = chrome_browser_net::kDnsOverHttpsModeSecure;
-    }
-    default_doh_templates = features::kDnsOverHttpsTemplatesParam.Get();
-  }
+  //NOTE: DoH fallback feature to insecure mode is not evaluated
   local_state_->SetDefaultPrefValue(prefs::kDnsOverHttpsMode,
-                                    base::Value(default_doh_mode));
+                                    base::Value(chrome_browser_net::kDnsOverHttpsModeOff));
   local_state_->SetDefaultPrefValue(prefs::kDnsOverHttpsTemplates,
-                                    base::Value(default_doh_templates));
-
-  // If the user has explicitly enabled or disabled the DoH experiment in
-  // chrome://flags, store that choice in the user prefs so that it can be
-  // persisted after the experiment ends. Also make sure to remove the stored
-  // prefs value if the user has changed their chrome://flags selection to the
-  // default.
-  flags_ui::PrefServiceFlagsStorage flags_storage(local_state_);
-  std::set<std::string> entries = flags_storage.GetFlags();
-  if (entries.count("dns-over-https@1")) {
-    // The user has "Enabled" selected.
-    local_state_->SetString(prefs::kDnsOverHttpsMode,
-                            chrome_browser_net::kDnsOverHttpsModeAutomatic);
-  } else if (entries.count("dns-over-https@2")) {
-    // The user has "Disabled" selected.
-    local_state_->SetString(prefs::kDnsOverHttpsMode,
-                            chrome_browser_net::kDnsOverHttpsModeOff);
-  } else {
-    // The user has "Default" selected.
-    local_state_->ClearPref(prefs::kDnsOverHttpsMode);
-  }
+                                    base::Value(features::kDnsOverHttpsTemplatesParam.Get()));
 
   PrefChangeRegistrar::NamedChangeCallback dns_pref_callback =
       base::BindRepeating(&OnStubResolverConfigChanged,
diff --git a/chrome/browser/ui/android/strings/android_chrome_strings.grd b/chrome/browser/ui/android/strings/android_chrome_strings.grd
--- a/chrome/browser/ui/android/strings/android_chrome_strings.grd
+++ b/chrome/browser/ui/android/strings/android_chrome_strings.grd
@@ -674,6 +674,17 @@ CHAR-LIMIT guidelines:
         Chrome Passwords
       </message>
 
+      <!-- DoH preferences -->
+      <message name="IDS_OPTIONS_DOH_EDIT_TITLE" desc="The title of the screen that allows users to change the URL that is used for DNS-over-HTTPS queries.">
+        Edit DoH template URLs
+      </message>
+      <message name="IDS_OPTIONS_DOH_EDIT_LABEL" desc="The label for the edit text field that allows the user to change the URL that is used for DNS-over-HTTPS queries.">
+        DoH template URLs
+      </message>
+      <message name="IDS_DOH_HELP" desc="The title of the hyperlink that allows users to visit the wiki page with instructions for DNS-over-HTTPS configuration.">
+        Visit help page
+      </message>
+
       <!-- Homepage preferences -->
       <message name="IDS_OPTIONS_HOMEPAGE_EDIT_TITLE" desc="The title of the screen that allows users to change the URL that opens when they tap on the home page button in the omnibox.">
         Edit home page
diff --git a/chrome/common/chrome_features.cc b/chrome/common/chrome_features.cc
--- a/chrome/common/chrome_features.cc
+++ b/chrome/common/chrome_features.cc
@@ -303,12 +303,12 @@ const char kDisallowUnsafeHttpDownloadsParamName[] = "MimeTypeList";
 
 // Enable DNS over HTTPS (DoH).
 const base::Feature kDnsOverHttps{"DnsOverHttps",
-                                  base::FEATURE_DISABLED_BY_DEFAULT};
+                                  base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Set whether fallback to insecure DNS is allowed by default. This setting may
 // be overridden for individual transactions.
 const base::FeatureParam<bool> kDnsOverHttpsFallbackParam{&kDnsOverHttps,
-                                                          "Fallback", true};
+                                                          "Fallback", false};
 
 // Supply one or more space-separated DoH server URI templates to use when this
 // feature is enabled. If no templates are specified, then a hardcoded mapping
-- 
2.17.1