Handle long press in PDF documents.

chrome/test/data/pdf/gesture_detector_test.js

 // Copyright 2016 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.
 
 chrome.test.runTests(function() {
   'use strict';
 
   class StubElement {
     constructor() {
       this.listeners = new Map([
@@ skipping 195 matching lines @@
       let pinchUpdateEvent = new MockTouchEvent('touchmove', [
         {clientX: 0, clientY: 0},
         {clientX: 0, clientY: 4}
       ]);
       stubElement.sendEvent(pinchUpdateEvent);
       chrome.test.assertEq('pinchupdate', pinchListener.lastEvent.type);
       chrome.test.assertTrue(pinchUpdateEvent.defaultPrevented);
 
       chrome.test.succeed();
     }
+
+    function testWasTwoFingerTouch() {
+      let stubElement = new StubElement();
+      let gestureDetector = new GestureDetector(stubElement);
+
+      let touchStartEvent = new MockTouchEvent('touchstart', [
+        {clientX: 0, clientY: 0, touches: []}

[Kevin McNee, 2017/05/03 17:25:43]

The array passed to MockTouchEvent's constructor is the |touches| array.

e.g.
Send a 1 finger touch start:
stubElement.sendEvent(new MockTouchEvent('touchstart', [
  {clientX: 0, clientY: 0},
]));

Send a 2 finger touch start:
stubElement.sendEvent(new MockTouchEvent('touchstart', [
  {clientX: 0, clientY: 0},
  {clientX: 0, clientY: 2}
]));

[dsinclair, 2017/05/03 18:13:38]

Awesome, thanks. I'd guessed and was going to start tracking down the failure
after lunch. (Didn't mean to commit this yet, got pulled in by accident when I
rebased)

+      ]);
+      stubElement.sendEvent(touchStartEvent);
+      chrome.test.assertFalse(gestureDetector.wasTwoFingerTouch());
+
+      touchStartEvent = new MockTouchEvent('touchstart', [
+        {clientX: 0, clientY: 0, touches: [1, 2]}
+      ]);
+      stubElement.sendEvent(touchStartEvent);
+      chrome.test.assertTrue(gestureDetector.wasTwoFingerTouch());
+
+      touchStartEvent = new MockTouchEvent('touchstart', [
+        {clientX: 0, clientY: 0, touches: [1, 2, 3]}
+      ]);
+      stubElement.sendEvent(touchStartEvent);
+      chrome.test.assertTrue(gestureDetector.wasTwoFingerTouch());
+    }

[Kevin McNee, 2017/05/03 17:25:43]

If you're relying on the value of |wasTwoFingerTouch()| to stick around after
the end of the gesture, you might want to assert that |wasTwoFingerTouch()|
stays true after a touchend.

stubElement.sendEvent(new MockTouchEvent('touchend', []));

[dsinclair, 2017/05/03 18:13:38]

Ah, good idea.

   ];
 }());