Add better handling for very, very small promo dialogs.

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 125 matching lines @@
 
     <!-- Minimum height/width for a touchable item -->
     <dimen name="min_touch_target_size">48dp</dimen>
 
     <!-- Promo dialogs -->
     <dimen name="promo_dialog_illustration_margin">24dp</dimen>
     <dimen name="promo_dialog_illustration_width">150dp</dimen>
     <dimen name="promo_dialog_padding">16dp</dimen>
     <dimen name="promo_dialog_max_width">600dp</dimen>
     <dimen name="promo_dialog_max_content_width">320dp</dimen>
+    <dimen name="promo_dialog_min_scrollable_height">100dp</dimen>
     <dimen name="promo_dialog_title_text_size">23sp</dimen>
     <dimen name="promo_dialog_normal_text_size">14sp</dimen>
 
     <!-- Data Saver -->
     <dimen name="data_usage_chart_height">252dp</dimen>
     <dimen name="data_reduction_main_menu_icon_width">32dp</dimen>
     <dimen name="data_saver_menu_footer_min_show_height">240dp</dimen>
 
     <!-- The size of the text for tab titles. -->
     <dimen name="compositor_tab_title_text_size">13sp</dimen>
@@ skipping 321 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>