Open hyperlinks in PDF in a new tab when middle mouse clicking.

chrome/browser/resources/pdf/pdf.js

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 'use strict';
 
 /**
  * @return {number} Width of a scrollbar in pixels
  */
 function getScrollbarWidth() {
@@ skipping 586 matching lines @@
           this.toolbar_.docLength =
               this.documentDimensions_.pageDimensions.length;
         }
         break;
       case 'email':
         var href = 'mailto:' + message.data.to + '?cc=' + message.data.cc +
             '&bcc=' + message.data.bcc + '&subject=' + message.data.subject +
             '&body=' + message.data.body;
         window.location.href = href;
         break;
+      case 'getLinkPositionReply':
+        var visiblePage = this.viewport_.getMostVisiblePage();
+        var visiblePageDimensions =
+            this.viewport_.getPageScreenRect(visiblePage);
+
+        var linkExists = false;
+        var viewportCoordinateX;
+        var viewportCoordinateY;
+        if (message.data.x !== undefined && message.data.y !== undefined) {
+          linkExists = true;
+          viewportCoordinateX = message.data.x + visiblePageDimensions.x;
+          viewportCoordinateY = message.data.y + visiblePageDimensions.y +
+              PDFViewer.MATERIAL_TOOLBAR_HEIGHT;
+        }
+
+        this.sendScriptingMessage_({
+          type: 'getLinkPositionReply',
+          linkExists: linkExists,
+          x: viewportCoordinateX,
+          y: viewportCoordinateY
+        });
+        break;
       case 'getPassword':
         // If the password screen isn't up, put it up. Otherwise we're
         // responding to an incorrect password so deny it.
         if (!this.passwordScreen_.active)
           this.passwordScreen_.active = true;
         else
           this.passwordScreen_.deny();
         break;
       case 'getSelectedTextReply':
         this.sendScriptingMessage_(message.data);
@@ skipping 155 matching lines @@
       return;
 
     // Delay scripting messages from users of the scripting API until the
     // document is loaded. This simplifies use of the APIs.
     if (this.loadState_ != LoadState.SUCCESS) {
       this.delayedScriptingMessages_.push(message);
       return;
     }
 
     switch (message.data.type.toString()) {
+      case 'getLinkPosition':
       case 'getSelectedText':
       case 'print':
       case 'selectAll':
         this.plugin_.postMessage(message.data);
         break;
     }
   },
 
   /**
    * @private
@@ skipping 82 matching lines @@
    * Each bookmark is an Object containing a:
    * - title
    * - page (optional)
    * - array of children (themselves bookmarks)
    * @type {Array} the top-level bookmarks of the PDF.
    */
   get bookmarks() {
     return this.bookmarks_;
   }
 };