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

chrome/browser/resources/pdf/pdf_scripting_api.js

 // Copyright 2014 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.
 
 /**
  * Turn a dictionary received from postMessage into a key event.
  * @param {Object} dict A dictionary representing the key event.
  * @return {Event} A key event.
  */
 function DeserializeKeyEvent(dict) {
@@ skipping 58 matching lines @@
                                         event.data.pageY,
                                         event.data.pageWidth,
                                         event.data.viewportWidth,
                                         event.data.viewportHeight);
         break;
       case 'documentLoaded':
         this.loadState_ = event.data.load_state;
         if (this.loadCallback_)
           this.loadCallback_(this.loadState_ == LoadState.SUCCESS);
         break;
+      case 'getLinkPositionReply':
+        if (this.getLinkPositionCallback_) {
+          this.getLinkPositionCallback_(event.data.x,
+                                        event.data.y);
+          this.getLinkPositionCallback_ = null;
+        }
+        break;
       case 'getSelectedTextReply':
         if (this.selectedTextCallback_) {
           this.selectedTextCallback_(event.data.selectedText);
           this.selectedTextCallback_ = null;
         }
         break;
       case 'sendKeyEvent':
         if (this.keyEventCallback_)
           this.keyEventCallback_(DeserializeKeyEvent(event.data.keyEvent));
         break;
@@ skipping 133 matching lines @@
   /**
    * Send a key event to the extension.
    * @param {Event} keyEvent the key event to send to the extension.
    */
   sendKeyEvent: function(keyEvent) {
     this.sendMessage_({
       type: 'sendKeyEvent',
       keyEvent: SerializeKeyEvent(keyEvent)
     });
   },
+
+  /**
+   * Get position for a link in the document.

[Lei Zhang, 2016/07/08 18:02:35]

Can you give a little more detail here, since PDFs can have more than 1 link.
Which one is being retrieved?

[jaepark, 2016/07/08 20:58:16]

Modified to

   /**
    * Get position of the first link in the most visible page of the document.
    * @return {boolean} true if the function is successful, false if there is an
    *     outstanding request that has not been answered.
    */

+   * @return {boolean} true if the function is successful, false if there is an
+   *     outstanding request that has not been answered.
+   */
+  getLinkPosition: function(callback) {
+    if (this.getLinkPositionCallback_)
+      return false;
+    this.getLinkPositionCallback_ = callback;
+    this.sendMessage_({
+      type: 'getLinkPosition',
+    });
+    return true;
+  },
 };
 
 /**
  * Creates a PDF viewer with a scripting interface. This is basically 1) an
  * iframe which is navigated to the PDF viewer extension and 2) a scripting
  * interface which provides access to various features of the viewer for use
  * by print preview and accessibility.
  * @param {string} src the source URL of the PDF to load initially.
  * @return {HTMLIFrameElement} the iframe element containing the PDF viewer.
  */
@@ skipping 11 matching lines @@
   // Add the functions to the iframe so that they can be called directly.
   iframe.setViewportChangedCallback =
       client.setViewportChangedCallback.bind(client);
   iframe.setLoadCallback = client.setLoadCallback.bind(client);
   iframe.setKeyEventCallback = client.setKeyEventCallback.bind(client);
   iframe.resetPrintPreviewMode = client.resetPrintPreviewMode.bind(client);
   iframe.loadPreviewPage = client.loadPreviewPage.bind(client);
   iframe.sendKeyEvent = client.sendKeyEvent.bind(client);
   return iframe;
 }