Max start velocity should be greater than zero.

components/test_runner/event_sender.cc

 // 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.
 
 #include "components/test_runner/event_sender.h"
 
 #include <stddef.h>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 1905 matching lines @@
 
   if (device_string == kSourceDeviceStringTouchpad) {
     event.sourceDevice = blink::WebGestureDeviceTouchpad;
   } else if (device_string == kSourceDeviceStringTouchscreen) {
     event.sourceDevice = blink::WebGestureDeviceTouchscreen;
   } else {
     args->ThrowError();
     return;
   }
 
+  float max_start_velocity = std::max(fabs(velocity_x), fabs(velocity_y));
+  if (!max_start_velocity) {
+    v8::Isolate* isolate = blink::mainThreadIsolate();
+    isolate->ThrowException(v8::Exception::TypeError(
+      gin::StringToV8(isolate, "Invalid max start velocity.")));
+    return;
+  }
+
   event.x = x;
   event.y = y;
   event.globalX = event.x;
   event.globalY = event.y;
 
   event.data.flingStart.velocityX = velocity_x;
   event.data.flingStart.velocityY = velocity_y;
   event.timeStampSeconds = GetCurrentEventTimeSec();
 
   if (force_layout_on_events_)
@@ skipping 920 matching lines @@
 }
 
 std::unique_ptr<WebInputEvent> EventSender::ScaleEvent(
     const WebInputEvent& event) {
   // ui::ScaleWebInputEvent returns nullptr when the scale is 1.0f as the event
   // does not have to be converted.
   return ui::ScaleWebInputEvent(event, delegate()->GetWindowToViewportScale());
 }
 
 }  // namespace test_runner