[ContextualSearch] Adds long press promo for Contextual Search.

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 57 matching lines @@
     <dimen name="infobar_margin">16dp</dimen>
     <!-- Width and height of the infobar icon. -->
     <dimen name="infobar_icon_size">36dp</dimen>
 
     <!-- App banner dimensions -->
     <dimen name="app_banner_icon_spacing">16dp</dimen>
 
     <!-- Contextual search dimensions -->
     <dimen name="contextual_search_bar_height">56dp</dimen>
     <dimen name="contextual_search_text_size">18sp</dimen>
+    <dimen name="contextual_search_peek_promo_height">48dp</dimen>
+    <dimen name="contextual_search_peek_promo_padding">12dp</dimen>
 
     <!-- Password generation popup dimensions -->
     <dimen name="password_generation_divider_height">1dp</dimen>
     <dimen name="password_generation_text_size">14sp</dimen>
     <dimen name="password_generation_horizontal_margin">10dp</dimen>
     <dimen name="password_generation_text_vertical_margin">12dp</dimen>
 
     <!--  Preferences dimensions -->
     <dimen name="pref_autofill_field_horizontal_padding">3dp</dimen>
     <dimen name="pref_autofill_field_top_padding">10dp</dimen>
@@ skipping 202 matching lines @@
     <dimen name="default_favicon_size">16dp</dimen>
 
     <!-- Media UI dimensions -->
     <!-- The media_session_icon_size is just big enough to make sure Android doesn't discard the
          icon but otherwise, the icon is meant to be a flat color so it doesn't really matter. -->
     <dimen name="media_session_icon_size">48dp</dimen>
 
     <!-- Offline pages dimensions -->
     <dimen name="offline_page_item_vertical_spacing">16dp</dimen>
 </resources>