MD History: Address design nits

chrome/browser/resources/md_history/history_item.html

 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/iron-flex-layout.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-checkbox/paper-checkbox.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button-light.html">
 <link rel="import" href="chrome://resources/html/icon.html">
 <link rel="import" href="chrome://resources/html/util.html">
 <link rel="import" href="chrome://history/browser_service.html">
 <link rel="import" href="chrome://history/constants.html">
 <link rel="import" href="chrome://history/searched_label.html">
 <link rel="import" href="chrome://history/shared_style.html">
 
 <dom-module id="history-item">
   <template>
     <style include="shared-style">
       :host {
         @apply(--layout-center);
         @apply(--layout-vertical);
         padding: 0 var(--history-item-padding-side, 0);
       }
 
       #main-container {
         background: #fff;
         border-color: var(--card-border-color);
+        border-radius: 2px;
         border-style: var(--border-style, solid);
         border-width: 0 1px;
         max-width: var(--card-max-width);
         min-width: var(--card-min-width);
         width: 100%;
       }
 
       :host([is-first-item]) #main-container {
         margin-top: var(--first-card-padding-top);
       }
@@ skipping 11 matching lines @@
         display: none;
       }
 
       :host([is-card-start]) #date-accessed {
         display: flex;
       }
 
       #item-container {
         @apply(--layout-center);
         @apply(--layout-horizontal);
-        min-height: 40px;
+        min-height: var(--item-height);
       }
 
       :host([is-card-start]) #item-container {
         padding-top: var(--card-first-last-item-padding);
       }
 
       :host([is-card-end]) #item-container {
         padding-bottom: var(--card-first-last-item-padding);
       }
 
       #title-and-domain {
         @apply(--layout-center);
         @apply(--layout-flex);
         @apply(--layout-horizontal);
-        min-height: 40px;
         overflow: hidden;
       }
 
       paper-checkbox {
         --paper-checkbox-checked-color: rgb(68, 136, 255);
         --paper-checkbox-size: 16px;
-        --paper-checkbox-unchecked-color: #969696;
+        --paper-checkbox-unchecked-color: var(--secondary-text-color);
         height: 16px;
         margin: 0 16px 0 20px;
         padding: 2px;
         width: 16px;
       }
 
       #time-accessed {
         color: #646464;
         min-width: 96px;
       }
 
       #domain {
         -webkit-margin-start: 16px;
-        color: #969696;
+        color: var(--secondary-text-color);
         flex-shrink: 0;
       }
 
       #menu-button {
         -webkit-margin-end: 12px;
         -webkit-margin-start: 2px;
-        color: #969696;
+        color: var(--secondary-text-color);
         height: 36px;
         width: 36px;
       }
 
       #menu-button iron-icon {
         height: 20px;
         width: 20px;
       }
 
       #bookmark-star {
@@ skipping 46 matching lines @@
           <iron-icon icon="cr:more-vert"></iron-icon>
         </button>
       </div>
       <template is="dom-if" if="[[hasTimeGap]]">
         <div id="time-gap-separator"></div>
       </template>
     </div>
   </template>
   <script src="chrome://history/history_item.js"></script>
 </dom-module>