Add rpcexplorer to webapp hierarchy.

web/inc/rpcexplorer/rpc-explorer.html

 <!--
   Copyright 2016 The LUCI Authors. All rights reserved.
   Use of this source code is governed under the Apache License, Version 2.0
   that can be found in the LICENSE file.
-  -->
+-->
 
 <link rel="import" href="../bower_components/app-router/app-router.html">
 <link rel="import" href="../bower_components/polymer/polymer.html">
 <link rel="import"
     href="../bower_components/html5-history-anchor/html5-history-anchor.html">
 <link rel="stylesheet"
     href="https://fonts.googleapis.com/css?family=Roboto:400,300,300italic,400italic,500,500italic,700,700italic">
 <link rel="import"
     href="../bower_components/google-signin/google-signin-aware.html">
 <link rel="import" href="../bower_components/paper-spinner/paper-spinner.html">
 
-<link rel="import" href="/static/common/rpc/rpc-client.html">
+<link rel="import" href="../rpc/rpc-client.html">
 
 <link rel="import" href="rpc-descriptor-util.html">
 <link rel="import" href="rpc-method.html">
 <link rel="import" href="rpc-service-list.html">
 <link rel="import" href="rpc-service.html">
 <link rel="import" href="../auth/auth-signin.html">
 
 <!-- The `rpc-explorer` is the top-level element of RPC Explorer -->
 <dom-module id="rpc-explorer">
   <template>
@@ skipping 146 matching lines @@
         }
       },
 
       _onRouted: function(e) {
         var model = e.detail.model || {};
         this.service = model.service || '';
         this.method = model.method || '';
       }
     });
   </script>
-</dom-module>
+</dom-module>