MD Downloads: fix up some Polymer 1.2.3 issues and re-vulcanize

R=michaelpg@chromium.org
BUG=none
TEST=new Polymer, same great downloads taste!
NOPRESUBMIT=true  # for long lines in crisper.js

Review URL: https://codereview.chromium.org/1462153007

Cr-Commit-Position: refs/heads/master@{#361262}

chrome/browser/resources/md_downloads/manager.css

@@ -7,6 +7,7 @@
   flex: 1 0;
   flex-direction: column;
   height: 100%;
+  overflow-y: overlay;
 }
 
 @media screen and (max-width: 1024px) {
@@ -15,23 +16,13 @@
   }
 }
 
-#panel {
-  --paper-header-panel-shadow: {
-    display: none;
-  };
-  --paper-header-panel-standard-container: {
-    display: flex;
-    overflow-y: overlay;
-  };
-}
-
 #no-downloads,
 #downloads-list {
   flex: 1;
 }
 
-.loading #no-downloads,
-.loading #downloads-list {
+:host([loading]) #no-downloads,
+:host([loading]) #downloads-list {
   display: none;
 }
 

chrome/browser/resources/md_downloads/manager.html

@@ -4,7 +4,6 @@
 <link rel="import" href="chrome://resources/html/util.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/polymer/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-list/iron-list.html">
-<link rel="import" href="chrome://resources/polymer/v1_0/paper-header-panel/paper-header-panel.html">
 <link rel="import" href="chrome://downloads/action_service.html">
 <link rel="import" href="chrome://downloads/constants.html">
 <link rel="import" href="chrome://downloads/i18n_setup.html">
@@ -13,8 +12,7 @@
 
 <dom-module id="downloads-manager">
   <template>
-    <paper-header-panel id="panel" class="loading">
-      <downloads-toolbar class="paper-header" id="toolbar"></downloads-toolbar>
+    <downloads-toolbar id="toolbar"></downloads-toolbar>
     <iron-list id="downloads-list" items="{{items_}}"
         hidden="[[!hasDownloads_]]">
       <template>
@@ -28,7 +26,6 @@
         <span><!-- Text populated in Manager#updateAll_(). --></span>
       </div>
     </div>
-    </paper-header-panel>
   </template>
   <link rel="import" type="css" href="chrome://downloads/shared_style.css">
   <link rel="import" type="css" href="chrome://downloads/manager.css">

chrome/browser/resources/md_downloads/manager.js

@@ -17,6 +17,10 @@ cr.define('downloads', function() {
       },
     },
 
+    hostAttributes: {
+      loading: true,
+    },
+
     /**
      * @param {Event} e
      * @private
@@ -99,7 +103,7 @@ cr.define('downloads', function() {
       if (loadTimeData.getBoolean('allowDeletingHistory'))
         this.$.toolbar.downloadsShowing = this.hasDownloads_;
 
-      this.$.panel.classList.remove('loading');
+      this.removeAttribute('loading');
     },
 
     /**

chrome/browser/resources/md_downloads/shared_style.css

@@ -6,6 +6,10 @@
   --downloads-item-width: 622px;
 }
 
+[hidden] {
+  display: none !important;
+}
+
 paper-button {
   font-weight: 500;
   margin: 0;

chrome/browser/resources/md_downloads/toolbar.css

@@ -26,7 +26,7 @@
   width: var(--downloads-item-width);
 }
 
-:host-context(.loading) #actions {
+:host-context([loading]) #actions {
   visibility: hidden;
 }