Disable pinch-to-zoom gesture on virtual keyboard

ui/keyboard/keyboard_event_filter.cc

+// Copyright 2017 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.
+
+#include "ui/keyboard/keyboard_event_filter.h"
+
+#include "ui/events/event.h"
+
+namespace keyboard {
+
+void KeyboardEventFilter::OnGestureEvent(ui::GestureEvent* event) {
+  switch (event->type()) {
+    case ui::ET_GESTURE_PINCH_BEGIN:
+    case ui::ET_GESTURE_PINCH_END:
+    case ui::ET_GESTURE_PINCH_UPDATE:
+      event->StopPropagation();
+      break;
+    default:
+      break;
+  }
+}
+
+}  // nemespace keyboard