WebUI: Replace vulcanize with polymer-bundler

docs/optimizing_web_uis.md

 # Optimizing Chrome Web UIs
 
 ## How do I do it?
 
 In order to build with a fast configuration, try setting these options in your
 GN args:
 
 ```
 use_vulcanize = true
 is_debug = false
 ```
 
 ## How is the code optimized?
 
 ### Resource combination
 
 [HTML imports](https://www.html5rocks.com/en/tutorials/webcomponents/imports/)
 are a swell technology, but can be used is slow ways.  Each import may also
 contain additional imports, which must be satisfied before certain things can
 continue (i.e. script execution may be paused).
 
 ```html
 <!-- If a.html contains more imports... -->
 <link rel="import" href="a.html">
 <!-- This script is blocked until done. -->
 <script> startThePageUp(); </script>
 ```
 
 To reduce this latency, Chrome uses a tool created by the Polymer project named
-[vulcanize](https://github.com/Polymer/polymer-bundler/tree/1.x).  It processes
+[polymer-bundler](https://github.com/Polymer/polymer-bundler).  It processes
 a page starting from a URL entry point and inlines resources the first time
 they're encountered.  This greatly decreases latency due to HTML imports.
 
 ```html
 <!-- Contents of a.html and all its dependencies. -->
 <script> startThePageUp(); </script>
 ```
 
 ### CSS @apply to --var transformation
 
@@ skipping 76 matching lines @@
 
 To mark a WebUI's resources compressed, you'll need to do something like:
 
 ```c++
 WebUIDataSource* data_source = WebUIDataSource::Create(...);
 data_source->SetDefaultResource(IDR_MY_PAGE);
 std::unordered_set<std::string> exclusions;
 exclusions.insert("strings.js");  // if required
 data_source->UseGzip(exclusions);
 ```