Make minimum PWA icon size the same accross all device densities

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 207 matching lines @@
     <dimen name="find_in_page_popup_margin_end">62dp</dimen>
 
     <!-- Web app dimensions
          There are three possible layouts for splash screens, which is chosen based on whether an
          icon was auto-generated by Chrome and whether the icon is bigger than a threshold. -->
     <dimen name="webapp_home_screen_icon_size">48dp</dimen>
 
     <dimen name="webapp_splash_offset">32dp</dimen>
     <dimen name="webapp_splash_image_size_ideal">128dp</dimen>
     <dimen name="webapp_splash_image_size_threshold">80dp</dimen>
-    <dimen name="webapp_splash_image_size_minimum">48dp</dimen>
+    <!-- Matches InstallableManager::GetMinimumIconSizeInPx() -->
+    <dimen name="webapp_splash_image_size_minimum">144px</dimen>

[dominickn, 2017/04/06 05:30:26]

This size is only used for splash screens. You haven't changed
webapp_home_screen_icon_size, which is what is actually used for launcher icons.
So the minimum PWA icon size remains device-density dependent.

 
     <dimen name="webapp_splash_small_image_size">80dp</dimen>
     <dimen name="webapp_splash_small_title_margin_top">32dp</dimen>
     <dimen name="webapp_splash_large_title_margin_bottom">16dp</dimen>
 
     <dimen name="webapk_badge_icon_size">24dp</dimen>
 
     <!-- Toolbar dimensions -->
     <dimen name="toolbar_tab_count_text_size_1_digit">12dp</dimen>
     <dimen name="toolbar_tab_count_text_size_2_digit">10dp</dimen>
@@ skipping 199 matching lines @@
     <dimen name="chrome_home_min_full_half_distance">160dp</dimen>
     <dimen name="chrome_home_progress_bar_height">4dp</dimen>
 
     <!--  Miscellaneous dimensions -->
     <dimen name="action_bar_shadow_height">10dp</dimen>
     <dimen name="card_corner_radius">2dp</dimen>
     <dimen name="list_item_corner_radius">3dp</dimen>
     <dimen name="list_item_lateral_padding">1dp</dimen>
     <dimen name="history_default_text_margin">16dp</dimen>
 </resources>