Add "Checking" spinner for server-side shipping address validation.

chrome/android/java/res/values/colors.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>
     <!-- Common colors -->
     <color name="default_text_color">#333</color>
     <color name="default_primary_color">#f2f2f2</color>
     <color name="light_normal_color">#5A5A5A</color>
     <color name="light_active_color">#4285F4</color>
     <color name="input_underline_color">#e5e5e5</color>
     <color name="input_underline_error_color">#d32f2f</color>
     <color name="explanation_text_color">#909090</color>
     <color name="text_highlight_color">#C6DAFC</color>
     <color name="dark_action_bar_color">#263238</color>
     <color name="descriptive_text_color">#646464</color>
     <color name="error_text_color">#c53929</color>
     <color name="google_blue_700">#3367d6</color>
+    <color name="disabled_text_color">#909090</color>

[gone, 2016/06/13 22:44:52]

Should just explanation_text_color where use currently use disabled_text_color. 
No need to redefine the same hex code twice.

[please use gerrit instead, 2016/06/13 23:07:09]

Done.

 
     <!-- Infobar colors -->
     <color name="infobar_accent_blue">#4285f4</color>
     <color name="infobar_descriptive_text_color">#646464</color>
 
     <!-- Snackbar colors -->
     <color name="snackbar_background_color">#282C32</color>
 
     <!-- Tab Switcher Colors -->
     <color name="tab_switcher_background">#14181C</color>
@@ skipping 152 matching lines @@
     <!-- Bottom bar colors -->
     <color name="bottom_bar_shadow_color">#1d000000</color>
 
     <!-- Payments UI colors -->
     <color name="payments_ui_scrim">#000000</color>
     <color name="payments_section_edit_background">#f5f5f5</color>
     <color name="payments_section_chevron">#b2b2b2</color>
     <color name="payments_section_separator">#e0e0e0</color>
 
 </resources>