Use a standalone AMP logo on the validator webui so it works in Firefox.

validator/index.js

@@ -310,7 +310,8 @@ var extToMime = {
   '.html': 'text/html',
   '.js': 'text/javascript',
   '.css': 'text/css',
-  '.png': 'image/png'
+  '.png': 'image/png',
+  '.svg': 'image/svg+xml'
 };
 
 /**

validator/webui/@polymer/ampproject-toolbar/ampproject-toolbar.html

@@ -35,7 +35,7 @@
       width: auto;
       text-transform: none;
       white-space: nowrap;
-      background-image: url('data:image/svg+xml;utf-8,<svg width=\22 14px\22  height=\22 14px\22  viewBox=\22 0 0 14 14\22  version=\22 1.1\22  xmlns=\22 http://www.w3.org/2000/svg\22  xmlns:xlink=\22 http://www.w3.org/1999/xlink\22 ><title>AMP Logo</title><g id=\22 Page-1\22  stroke=\22 none\22  stroke-width=\22 1\22  fill=\22 none\22  fill-rule=\22 evenodd\22 ><g id=\22 AMP-Logo\22  fill=\22 #0379C4\22 ><path d=\22 M8.657817,0.216062 L7.647297,5.589962 L10.085327,5.589962 C10.188787,5.589962 10.256477,5.698322 10.211117,5.791282 L6.230217,13.958532 C6.480467,13.985622 6.734567,13.999972 6.992097,13.999972 C10.853717,13.999972 13.984117,10.869572 13.984117,7.007952 C13.984117,3.720402 11.715067,0.963312 8.657817,0.216062\22  id=\22 Fill-4\22 ></path><path d=\22 M6.425398,8.529948 L3.987158,8.529948 C3.883698,8.529948 3.815938,8.421588 3.861298,8.328628 L7.885808,0.072478 C7.591808,0.034958 7.292138,0.015708 6.987848,0.015848 C3.168228,0.018088 0.028028,3.136308 0.000168,6.955858 C-0.024192,10.303328 2.304078,13.111168 5.429718,13.824608 L6.425398,8.529948 Z\22  id=\22 Fill-1\22 ></path></g></g></svg>');
+      background-image: url('/logo-blue.svg');
       background-repeat: no-repeat;
       background-size: 40px 40px;
       background-position: center left;

validator/webui/app.yaml

@@ -16,3 +16,8 @@ handlers:
   static_files: amp_favicon.png
   upload: amp_favicon\.png$
   secure: always
+
+- url: /logo-blue.svg$
+  static_files: logo-blue.svg
+  upload: logo-blue\.svg$
+  secure: always