[Experimental - DO NOT LAND] Use border-image for MD History shadows.

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/cr/ui/focus_row.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/polymer/v1_0/paper-styles/shadow.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">
@@ skipping 23 matching lines @@
       }
 
       :host(:not([embedded])) #sizing-container {
         @apply(--card-sizing);
       }
 
       :host([is-card-end]) #main-container {
         margin-bottom: var(--card-padding-between);
       }
 
-      :host([is-card-start][is-card-end]) #main-container {
-        border-radius: 2px;
+      :host([is-card-start]) #main-container {
       }
 
       #date-accessed {
         display: none;
       }
 
       :host([is-card-start]) #date-accessed {
         display: block;
       }
 
@@ skipping 100 matching lines @@
 
       #time-gap-separator {
         -webkit-border-start: 1px solid #888;
         -webkit-margin-start: 77px;
         height: 15px;
       }
 
       #background-clip {
         /* Prevent artifacts when zoomed by overlapping the next item. */
         bottom: -0.4px;
-        clip: rect(auto 999px auto -5px); /* Clip the top and bottom edges. */
         left: 0;
         position: absolute;
         right: 0;
         top: 0;
         z-index: -1;
       }
 
       :host([is-card-end]) #background-clip {
         bottom: 0;
-        clip: rect(auto 999px 500px -5px); /* Clip the top edge. */
       }
 
       #background {
-        @apply(--shadow-elevation-2dp);
+        z-index: -1;
         background: #fff;
         bottom: 0;
-        left: 0;
+        left: -7px;
         position: absolute;
-        right: 0;
+        right: -7px;
         top: 0;
+
+        border-image-source: url('/images/100/shadow_border.png');
+        border-image-repeat:  strech;
+        border-style: solid;
+        border-image-slice: 30;
+        border-width: 0 20px 0px 20px;
+        background: #fff;
+      }
+
+      :host([is-card-start]) #background {
+        border-width: 20px 20px 0px 20px;
+        top: -7px;
+      }
+
+      :host([is-card-end]) #background {
+        border-width: 0 20px 20px 20px;
+        bottom: -7px;
       }
 
       :host([embedded]) #background {
         display: none;
       }
 
-      :host(:not([is-card-start])) #background {
-        top: -5px; /* Draw the box shadow up the full edge of the background. */
-      }
-
-      :host([is-card-start]) #background {
-        border-radius: 2px 2px 0 0;
-      }
-
-      :host([is-card-end]) #background {
-        border-radius: 0 0 2px 2px;
-      }
-
-      :host([is-card-start][is-card-end]) #background {
-        border-radius: 2px;
-      }
     </style>
 
     <div id="sizing-container">
       <div id="main-container">
-        <div id="background-clip">
-          <div id="background"></div>
-        </div>
+        <div id="background"></div>
         <div id="date-accessed" class="card-title">
           [[cardTitle_(numberOfItems, item.dateRelativeDay, searchTerm)]]
         </div>
         <div id="item-container">
           <button is="paper-icon-button-light" id="checkbox"
               on-mousedown="onCheckboxMousedown_"
               on-click="onCheckboxSelected_"
               disabled="[[selectionNotAllowed_()]]"
               role="checkbox"
               aria-checked$="[[getAriaChecked_(selected)]]"
@@ skipping 26 matching lines @@
             <div></div>
             <div></div>
           </button>
         </div>
         <div id="time-gap-separator" hidden="[[!hasTimeGap]]"></div>
       </div>
     </div>
   </template>
   <script src="chrome://history/history_item.js"></script>
 </dom-module>