[Android] Use fallback icon if there is no large favicon on the history page

chrome/browser/resources/history/history_mobile.css

 /* Copyright (c) 2013 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. */
 
 /* This file contains styles specific to Android and iOS. */
 
 html:not(.focus-outline-visible) :focus {
   outline: none;
 }
 
@@ skipping 178 matching lines @@
   opacity: 0;
 }
 
 .entry input[type=checkbox] {
   display: none;
 }
 
 .entry .visit-entry {
   -webkit-flex: auto;
   -webkit-flex-flow: column;
-  -webkit-padding-start: 48px;
-  background-size: 32px;
+  -webkit-padding-start: 16px;
   line-height: 1.3;
 }
 
 .entry .visit-entry.blocked-indicator {
   line-height: 2;
 }
 
 .entry .visit-entry :-webkit-any(a, .domain) {
   display: block;
   margin-left: 0;
   margin-right: 0;
   min-width: 0;
   overflow: hidden;
   padding-left: 0;
   padding-right: 0;
   text-overflow: ellipsis;
   white-space: nowrap;
 }
 
 .entry .visit-entry.blocked-indicator a {
   display: inline;
 }
 
+.favicon {
+  background-size: 32px;

[Dan Beam, 2016/02/06 03:34:29]

i now understand what you mean: you're returning the dominant color and
stretching it to 32x32. sneaky. as long as this is fast enough, I suppose I'm OK
with this, but I understand newt@'s apprehension now...

for what it's worth: you can probably paint the image's content onto a canvas
and scrape the pixel at (0,0), but dunno if that's really better

https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/dra...
https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/get...

+  height: 32px;
+  width: 32px;
+}
+
+.fallback-favicon {
+  border-radius: 2px;
+  color: white;
+  font: bold 20px/32px sans-serif;
+  text-align: center;
+}
+
 .entry .domain {
   font-size: 14px;
 }
 
 #older-button {
   -webkit-padding-end: 16px;
 }
 
 #newest-button {
   -webkit-padding-start: 16px;
@@ skipping 91 matching lines @@
 
 .ios-keyboard-visible #scrolling-container {
   /* Should be 0, but that breaks scrolling -- see crbug.com/292715. */
   bottom: -1px;
 }
 
 #results-header:empty {
   display: none;
 }
 </if> /* is_ios */