Handle long press in PDF documents.

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 227 matching lines @@
       this.browserApi_.setZoom.bind(this.browserApi_),
       this.browserApi_.getInitialZoom());
   this.viewport_.zoomManager = this.zoomManager_;
   this.browserApi_.addZoomEventListener(
       this.zoomManager_.onBrowserZoomChange.bind(this.zoomManager_));
 
   // Setup the keyboard event listener.
   document.addEventListener('keydown', this.handleKeyEvent_.bind(this));
   document.addEventListener('mousemove', this.handleMouseEvent_.bind(this));
   document.addEventListener('mouseout', this.handleMouseEvent_.bind(this));
+  document.addEventListener('contextmenu',
+      this.handleContextMenuEvent_.bind(this));
 
   var tabId = this.browserApi_.getStreamInfo().tabId;
   this.navigator_ = new Navigator(
       this.originalUrl_, this.viewport_, this.paramsParser_,
       new NavigatorDelegate(tabId));
   this.viewportScroller_ =
       new ViewportScroller(this.viewport_, this.plugin_, window);
 
   // Request translated strings.
   chrome.resourcesPrivate.getStrings('pdf', this.handleStrings_.bind(this));
@@ skipping 145 matching lines @@
     }
   },
 
   handleMouseEvent_: function(e) {
     if (e.type == 'mousemove')
       this.toolbarManager_.handleMouseMove(e);
     else if (e.type == 'mouseout')
       this.toolbarManager_.hideToolbarsForMouseOut();
   },
 
+  handleContextMenuEvent_: function(e) {
+    // Stop Chrome from popping up the context menu on long press. We need to
+    // make sure the start event had 2 touches (which corresponds to our

[Kevin McNee, 2017/05/02 23:18:19]

Don't you mean "the start event did not have 2 touches"?

[dsinclair, 2017/05/03 14:18:40]

Done.

+    // touchStartEvent_) because we don't want to block two finger tap opening
+    // the context menu. We check for firesTouchEvents in order to not block
+    // the context menu on right click.
+    if (e.sourceCapabilities.firesTouchEvents &&
+        !this.gestureDetector_.isTwoFingerTouch()) {
+      e.preventDefault();
+    }
+  },
+
   /**
    * @private
    * Rotate the plugin clockwise.
    */
   rotateClockwise_: function() {
     this.plugin_.postMessage({
       type: 'rotateClockwise'
     });
   },
 
@@ skipping 500 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_;
   }
 };