[MD History] Color tweaks.

chrome/browser/resources/md_history/history_toolbar.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/cr_elements/cr_lazy_render/cr_lazy_render.html">
 <link rel="import" href="chrome://resources/cr_elements/cr_toolbar/cr_toolbar.html">
 <link rel="import" href="chrome://history/browser_service.html">
 <link rel="import" href="chrome://history/icons.html">
 <link rel="import" href="chrome://history/shared_style.html">
 
 <!-- Lazy loaded: iron-dropdown, paper-button, paper-icon-button-light,
@@ skipping 14 matching lines @@
       cr-toolbar,
       #overlay-buttons,
       #overlay-wrapper,
       #toolbar-container {
         align-items: center;
         display: flex;
         width: 100%;
       }
 
       :host([items-selected_]) {
-        background: rgb(68, 136, 255);
+        background: var(--interactive-color);
       }
 
       #toolbar-container {
         height: var(--toolbar-height);
       }
 
       cr-toolbar {
         --cr-toolbar-field-end-padding: 0;
         --cr-toolbar-field-margin: var(--side-bar-width);
         --cr-toolbar-right-content-wide: {
@@ skipping 37 matching lines @@
       }
 
       iron-dropdown {
         margin-top: 28px;  /** Height of icon + 8px spacing. */
       }
 
       .dropdown-content {
         @apply(--shadow-elevation-2dp);
         background-color: white;
         border-radius: 2px;
-        color: var(--paper-grey-800);
+        color: var(--primary-text-color);
         overflow: hidden;
         padding: 12px 20px;
       }
 
       /* Selection overlay. */
 
       :host(:not([has-drawer])) #overlay-wrapper {
         -webkit-margin-start: var(--side-bar-width);
       }
 
@@ skipping 162 matching lines @@
               on-tap="onNextTap_"
               disabled="[[isToday_(groupedOffset)]]">
             <iron-icon icon="cr:chevron-right"></iron-icon>
           </button>
         </div>
       </div>
     </template>
   </template>
   <script src="chrome://history/history_toolbar.js"></script>
 </dom-module>