Fire accessibilityPrivate events on two-finger hold gesture.

chrome/common/extensions/api/accessibility_private.json

Index: chrome/common/extensions/api/accessibility_private.json
diff --git a/chrome/common/extensions/api/accessibility_private.json b/chrome/common/extensions/api/accessibility_private.json
index 64baa42b84a1dcc13975f49a4596a5705b18be91..0b9f629f1defebdc7057e17d586e91fc53bd6e91 100644
--- a/chrome/common/extensions/api/accessibility_private.json
+++ b/chrome/common/extensions/api/accessibility_private.json
@@ -118,6 +118,18 @@
             "$ref": "Gesture"
           }
         ]
+      },
+      {
+        "name": "onTwoFingerTouchStart",
+        "type": "function",
+        "description": "Fired when we first detect two fingers are held down, which can be used to toggle spoken feedback on some touch-only devices.",
+        "parameters": []
+      },
+      {
+        "name": "onTwoFingerTouchStop",
+        "type": "function",
+        "description": "Fired when  the user is no longer holding down two fingers (including releasing one, holding down three, or moving them).",
+        "parameters": []
       }
     ]
   }