🔍 Introduce default search engine dialog

chrome/android/java/res/values/dimens.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright 2014 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. -->
 
 <resources>
     <!-- Connection info popup dimensions -->
     <dimen name="connection_info_padding_wide">24dp</dimen>
     <dimen name="connection_info_padding_thin">16dp</dimen>
 
@@ skipping 406 matching lines @@
     <dimen name="pref_autofill_dropdown_bottom_margin">16dp</dimen>
     <dimen name="pref_autofill_touch_target_padding">15dp</dimen>
     <dimen name="pref_child_account_reduced_padding">4dp</dimen>
 
     <dimen name="pref_icon_padding">4.6dp</dimen>
     <dimen name="pref_spinner_padding_end">8dp</dimen>
 
     <!-- Dialog dimensions.
          https://www.google.com/design/spec/components/dialogs.html#dialogs-simple-dialogs -->
     <dimen name="dialog_width_unit">56dp</dimen>  <!-- MD dialog widths are multiples of this. -->
+    <dimen name="dialog_header_margin">14dp</dimen>
     <dimen name="separator_height">1dp</dimen>
 
     <!-- Downloads dimensions. -->
     <dimen name="downloads_item_icon_size">48dp</dimen>
     <dimen name="downloads_item_margin">16dp</dimen>
 
     <!-- SelectableListLayout dimensions -->
     <dimen name="selectable_list_layout_end_icon">24dp</dimen>
     <dimen name="selectable_list_layout_row_end_padding">16dp</dimen>
     <dimen name="selectable_list_layout_start_icon_width">56dp</dimen>
@@ skipping 31 matching lines @@
     <dimen name="context_menu_header_image_min_size">56dp</dimen>
     <dimen name="context_menu_header_image_max_size">56dp</dimen>
     
     <!-- Divider Dimensions -->
     <dimen name="divider_height">1dp</dimen>
 
     <!-- Search widget dimensions -->
     <dimen name="search_activity_location_bar_margin_start">16dp</dimen>
     <dimen name="search_activity_location_bar_margin_end">8dp</dimen>
 </resources>